enable LLVM/Clang in Travis
fix clang operator<< argument-dependant lookup, ambiguity
This removes matplotlib as a dependency by default.  Along with it, clear out some un-used code
Deleted integration test which relied on ImageSensor
Restoring ImageSensor.py and network serialization integration test
enable LLVM/Clang in Travis
fix clang operator<< argument-dependant lookup, ambiguity
build opt -Qunused-parameter for clang

to don't mind -falign-loops=16 which clang does not know
use var _MATH here
switch gcc/clang specific compile flags
implement stringstream operator<< for vector

it's used by Index and was breaking clang.
final Clang support

tested on clang 3.2, 3.4.
use CC=clang CXX=clang++ ./cleanbuild.sh
(if you dont have gcc on you system, the CC,CXX above is unnecessary)
)
Merge branch 'llvm-support' of https://github.com/breznak/nupic into llvm-support

Conflicts:
	nta/utils/LoggingException.hpp
Merge pull request #302 from breznak/llvm-support

LLVM/Clang support
Except all when importing
Slightly more graceful approach to initializing pylab if it's available.
Merge remote-tracking branch 'upstream/master' into optional-matplotlib
Merge pull request #377 from oxtopus/optional-matplotlib

Matplotlib no longer required by default
testing