Add base content straight from example/fetch.c. Pretty much.
Add fs.{c,h} files for upcoming POSIX paths support.
Add new 'fs.o' file to Tupfile dependency.
Merge branch 'feature/filesystem' into develop

Conflicts:
	src/Tupfile
Add Tupfile for building files
Merge 'Tupfile' from 'develop' into 'feature/repoctrl'
Merge branch 'feature/repoctrl' into develop