Address review comments
Integer output data editing (I,B,O,Z)
Full integer output formatting
Stub out some work in progress
Progress on E output data editing
E, D, EN, and ES output editing done
Fw.d output editing
Real G output editing
G output editing for reals
Make environment a distinct module
CHARACTER and LOGICAL output editing
Minimal decimal representations for E0, F0, G0 editing
Move real output editing code into its own file
Fix/dodge some GCC build problems
Prep work for external I/O statement state
External HELLO, WORLD
Fix build problem with GCC
Add virtual destructors where needed
Add new test
Original-commit: flang-compiler/f18@c3f1774f8e
Reviewed-on: https://github.com/flang-compiler/f18/pull/950
Updated CMake files accordingly, using better regex
Updated license headers to match new extension and fit within 80 columns
Updated other comments within files that referred to the old extension
Original-commit: flang-compiler/f18@ae7721e611
Reviewed-on: https://github.com/flang-compiler/f18/pull/958