Software implementation for N0278:
1. Added VPS encoding in encoder
2. Add new project StreamMergeApp to N-to-1 bitstream merge
3. Changed decoder to support only decoding the specified layer stream

- remove unnecessary build scripts
- allow MSYS32/64 build
- small feature improvements, e.g. allow targeting major compiler options for build parameters

- remove HighPrecision MV option
- fixes for statistics output
- removal of SVN header integration (fixes issue with Xcode)