For query-file-tests use lit methods for writing messages about
configuration.
Enforce that the python version used when running OutputCheck is the
same that was detected as CMake configure time.
Eliminating unnecessary dependency on zlib

Fixes issue #16
Merge branch 'master' of https://github.com/stp/stp
Resolve minor GCC warnings in c_interface.cpp
Resolve minor GCC warnings in various headers

In particular, these are the ones that show up when compiling
c_interface.cpp with g++ 4.5.2.