Added some minor comments after discussions with Ron. Focused in
part on legacy code we don't need anymore.
Added TODO's for some of the comments
Merge pull request #233 from subutai/minor_clamodel_comments

Added some minor comments after discussions with Ron. Focused in part on legacy code we don't need anymore. This is to prepare for a later cleanup phase.
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
Merge branch 'master' into modular-matplotlib