Add note about submodule status
Use GitHub for contributors
Run tests by default

Also fixes some other dependencies.
Merge branch 'patch-1' of https://github.com/akkartik/carp
long long -> carp_value
short int -> carp_bool; finished types... for now?
change stack_full testing by one
make more consistent 0/1 instead of occasional -1
not actually off-by-one; stack has one more space than it needs
add more to stack
debug stuff in tests
ht tests
add file pointers to print functions
fp defaults to stdout in stack print too
update todo