tk: Simplify tk_info()
ast: Solve out astSetType()
cpp: Simplify cppLookupMacro()
util: Remove hashtb stats code
Remove -inclib option

#inclibs can just aswell be added afterwards - letting fbfrog do it has no
advantage.
tests: Add test case showing an #include guard detection bug

recursive-a.h isn't being included recursively, but it should be.
cpp: Fix #include guard detection to handle recursive #includes