Now src contains exactly what's embedded in mongoose.c and .h, nothing more.
Added `tools/amalgam.sh` to aamlgamate both files at once.
There are no functional changes to mongoose.c, .h in this PR, only slight filename changes.
In certain files it was necessary to make tests work from public
mongoose repo, so this commit makes things consistent.
PUBLISHED_FROM=694454d0ff007229c65d524a2a2beaf126420f15