Rename namespace specreader to spec.
Move source of SpecReader to SpecReader.cpp.
Create namespace apngasm::spec::priv.
Refactor SpecReader.
Rename SpecReader to SpecParser.
Rename ISpecReaderImpl to ISpecReader.
Optimize lib/CMakeLists.txt.
Add empty methods.
comment miss.
Create SpecWriter.
Output empty json file.