* change TSEncoding.GORILLA to TSEncoding.GORILLA_V1
* add the implementation framework for GORILLA_V2
* support encoding INT32 using GORILLA_V2 encoder
* add the encoders of GORILLA_V2
* add the decoders of GORILLA_V2
* fix tests
* fix tests
* add copyright info in LICENSE
* add copyright info in modified files
* fix bugs and add ITs
* add IT
* update Gorilla encoding user doc
* fix code smells
* change the return type of the method readNextClearBit to byte
* rename default Gorilla encoding to GORILLA
* remove unbundled dependencies from NOTICE and NOTICE-binary; add License-binary
* move some license declaration from LICENSE to LICENSE-binary
* add NOTICE-binary and LICENSE-binary to the binary tar.gz file
* rename License to LICENSE
* add source code declaration with MavenWrapper
* change the root name as incubating-iotdb-parent
* add DISCLAIMER file