modular: numpy - remove source dirs

for linux and MacOS
numpy: use pip install dependency

numpy 1.6.2 was/is used

Conflicts:
	external/common/requirements.txt
numpy installed by pip fix includes
modular numpy: dont copy files,

pip already instelled them in proper location
numpy: update to the latest stable version

from 1.6.2 -> 1.7.1
release notes http://sourceforge.net/projects/numpy/files/NumPy/1.7.0/

Conflicts:
	external/common/requirements.txt
add source tarball for numpy to pip cache
remove numpy license, it's a dependency now
hack for matplotlib's pip install problems - numpy dep

workaround for matplotlib and asteval install bug: - numpy must already be installed
see http://stackoverflow.com/questions/11797688/matplotlib-requirements-with-pip-install-in-virtualenv
https://github.com/matplotlib/matplotlib/wiki/MEP11

numpy must be already installed, and requirements.txt file does not work, so do it manually
in build.sh before calling requirements.txt file

Conflicts:
	build.sh
	external/common/requirements.txt
numpy installed by pip fix includes

also remove old comments
and fix numpy includes for swig! (might fix some errors we had)
numpy: update to the latest stable version

from 1.6.2 -> 1.7.1
release notes http://sourceforge.net/projects/numpy/files/NumPy/1.7.0/

Conflicts:
	external/common/requirements.txt
add source tarball for numpy to pip cache
remove numpy license, it's a dependency now
hack for matplotlib's pip install problems - numpy dep

workaround for matplotlib and asteval install bug: - numpy must already be installed
see http://stackoverflow.com/questions/11797688/matplotlib-requirements-with-pip-install-in-virtualenv
https://github.com/matplotlib/matplotlib/wiki/MEP11

numpy must be already installed, and requirements.txt file does not work, so do it manually
in build.sh before calling requirements.txt file

Conflicts:
	build.sh
	external/common/requirements.txt
Merge branch 'modular-numpy' of https://github.com/breznak/nupic into modular-numpy

Conflicts:
	build.sh
	build_system/unix/Includes.am
Update configuration tests to handle ParseError (in addition to ExpatError)
allow python 2.7 in Travis CI
add add_to_path shell function in build.sh

requires 1 arg - new path,
add it to the PATH only once (script is called repetitively)
eg add_to_path /home/joe/nta/eng
export NUPIC_INSTALL addition to PATH

we use it to pip install,
but later tests failed when python was called without this addition.

This fixes the functionality
export pythonpath too
Specify python version in env.sh