source resturcturing + CMake
cmake update, added template test
spliting header implementation into cpp files, routing.cpp created
improve mustache.h
decide to be header only
now crow becomes completely header only
amalgamation added
Merge branch 'directory-restructuring'

Directory structure changed.
Crow becomes a complete header-only library with http_parser_merged.h.
Provides amalgamated crow_all.h (all feature in one header file).