Added 'simple.cpp' which does the bare mimimum to confirm the amalgamation worked (compiled and run after the combine step). Split the embedded .basis files from the Emscripten test so they can be shared. Fixed an error in the creation script (which caused it to always fail). Corrected the syntax for the unused functions (tested with older, less forgiving compilers).
Renamed the generated file to be the same as the non-amalgamated file, updating the script (and docs) accordinly. Added an example of generated amalgamated header and source.
