update VMD molfile plugin headers and move them to lib/molfile (where they belong)

lib/molfile/Makefile.lammps

@@ -6,6 +6,9 @@
 # When you build LAMMPS with the USER-MOLFILE package installed, it will
 # use the 3 settings in this file.  They should be set as follows.
 # 
+# The molfile_SYSINC setting is to point to the folder with the VMD
+# plugin headers. By default it points to bundled headers in this folder
+# 
 # The molfile_SYSLIB setting is for a system dynamic loading library
 # that will be used to load the molfile plugins.  It contains functions
 # like dlopen(), dlsym() and so on for dynamic linking of executable
@@ -24,7 +27,10 @@
 
 # Settings that the LAMMPS build will import when this package is installed
 
-molfile_SYSINC =
+# change this to -I/path/to/your/lib/vmd/plugins/include if the bundled
+# header files are incompatible with your VMD plugsins
+molfile_SYSINC =-I../../lib/molfile
+#
 ifneq ($(LIBOBJDIR),/Obj_mingw32)
 ifneq ($(LIBOBJDIR),/Obj_mingw64)
 ifneq ($(LIBOBJDIR),/Obj_mingw32-mpi)

lib/molfile/README

@@ -6,17 +6,30 @@ and write_dump commands in a LAMMPS input script.
 More information about the VMD molfile plugins can be found at
 http://www.ks.uiuc.edu/Research/vmd/plugins/molfile.
 
-More specifically, to be able to dynamically load and execute the
-plugins from inside LAMMPS, you need to link with a system library
-containing functions like dlopen(), dlsym() and so on for dynamic
-linking of executable code into an executable.  This library is
-defined by setting the molfile_SYSLIB variable in the Makefile.lammps
-file in this dir.
+NOTE: while the programming interface (API) of the VMD molfile plugins
+is backward compatible (i.e. you can expect to be able to compile this
+package for plugins from newer VMD packages), the binary interface
+(ABI) is not.  So it is necessary to compile this package with the
+VMD molfile plugin header files (vmdplugin.h and molfile_plugin.h) 
+matching VMD installation that the (binary) plugin files are taken from.
+These header files can be found inside the VMD installation tree under
+"plugins/include". For convenience, this package includes a set of
+header files that is compatible with VMD 1.9.3 (the current version
+in April 2017). You need to adjust the molfile_SYSINC variable in the
+Makefile.lammps file in this directory, in case you want to use VMD
+molfile plugins from a different version. The interface is compatible
+with plugins starting from VMD version 1.8.4.
+
+In order to be able to dynamically load and execute the plugins from
+inside LAMMPS, you need to link with a system library containing functions
+like dlopen(), dlsym() and so on for dynamic linking of executable code
+into an executable.  This library is defined by setting the molfile_SYSLIB
+variable in the Makefile.lammps file in this dir.
 
 For Linux and most current unix-like operating systems, this can be
 kept at the default setting of "-ldl" (on some platforms this library
 is called "-ldld").  For compilation on Windows, a slightly different
 mechanism is used that is part of the Windows programming environment
-and this library is not needed.
+and this kind of library is not needed.
 
 See the header of Makefile.lammps for more info.

src/USER-MOLFILE/README

@@ -2,8 +2,8 @@ This package provides a C++ interface class to the VMD molfile
 plugins, http://www.ks.uiuc.edu/Research/vmd/plugins/molfile, and a
 set of LAMMPS classes that use this interface.
 
-Molfile plugins provide a consistent programming interface to read and
-write file formats commonly used in molecular simulations.  This
+Molfile plugins provide a consistent programming interface to read
+and write file formats commonly used in molecular simulations.  This
 package only provides the interface code, not the plugins; these can
 be taken as precompiled binaries directly from a VMD installation that
 matches the platform of your LAMMPS executable.  Using the plugin
@@ -18,17 +18,5 @@ LAMMPS, you need to link with an appropriate system library, which
 is done using the settings in lib/molfile/Makefile.lammps.  See
 that file and the lib/molfile/README file for more details.
 
-NOTE: while the programming interface (API) to the molfile plugins is
-backward compatible (i.e. you can expect to be able to compile this
-package for plugins from newer VMD packages), the binary interface
-(ABI) is not.  So it is necessary to compile this package with the
-molfile plugin header files (vmdplugin.h and molfile_plugin.h) taken
-from the _same_ VMD installation that the (binary) plugin files are
-taken from.  These header files can be found inside the VMD
-installation tree under: "plugins/include".
-
-For convenience, this package includes a set of header files that is
-compatible with VMD 1.9.3 (the current version in April 2017)
-
 The person who created this package is Axel Kohlmeyer at Temple U
 (akohlmey at gmail.com).  Contact him directly if you have questions.