remove matplotlob source files
pip install, update (old) matplotlib

installed by pip now
(was causing some problems, might fallback to non-working mpl on some Macs, it's OK)

was 0.91.1 recent stable is 1.2.1, chosen here is 1.1.1 -
new enough to build with gcc48 and numpy1.7, and old enough no API changes to code need to be applied.

fixes Mac support, gcc problems, improves graphics, see
http://matplotlib.org/users/whats_new.html

please test new functionality

Conflicts:
	external/common/requirements.txt
remove pytz, provided in recent matplotlib

see https://bugs.archlinux.org/task/16327
added matplotlib license
change include order, make nupic's numpy go first

this was not clearly an error, but avoids potential trouble,
use the numpy shipped with nupic first in includes (not a system wide numpy,
iff there was such)
lib freetype(2) is listed as a dependency

some configs had trouble building w/o it (NPC-369), so we're listing it here.
add fallback if matplotlib is not working properly

we've been experiencing some issues with matplotlib installed with pip
(on Macs, some Linux missing freetype etc), one suggestion was to remove it completely,
as the fucntionality is only needed for some visualisations and examples.

This way we can keep it around for users who need it, we install it, if it runs on system, we're fine,
if there are problems, we fallback to option where it's not used (tests pass fine, some examples might be broke)

See https://issues.numenta.org/browse/NPC-371 and PR #141
remove custom pylab.py, use the one provided in matplotlib

we had a pylab.py file that was importing the matplotlib.pylab anyway,
go with the upstream pylab, simplify and maybe fix some problems