Update SubType.hs

Simplifying example to show that the issue is not polymorphic instantiation but the counterintuitive nature of function sub typing...
add CountBinders.hs to count the number of recursive binders / functions
in a module
use varType instead of matching on Expr
Merge branch 'master' of github.com:ucsd-progsys/liquidhaskell
add binder count to metrics.py
s/nonterm/serious/
can remove some annots in List
add # unique error spans
Asdasd
RBTree-mini.hs
subsFreeSyms on invariants as well
ASdaSDA
asd

Merge branch 'master' of github.com:ucsd-progsys/liquidhaskell
RB-insert works
explicit binders added to prevent silly RBT type strengthening
aasd
about to revert color
thing is still not working...
invariants over constructors still not working
forgot to add invariants to makeSymbols...