Refactored CMakeLists.txt to use nupic.core as an external library and not require direct access to the source repository
Updated nupic.core
Update nupic.core to version that includes the right .a
Specify python lib during install
Remove find_package(PythonLibs ...) which was resulting in a conflicting version being found
Remove python 2.6 from travis build matrix
Fixup Dockerfile to remove redundant build, and develop steps as well as use correct WORKDIR value
Merge branch 'remove-2.6-support' into cmake-cleanup