Splits out FeatureMapper code into a submodule

Commit moves large amount of code into the featuremapper submodule,
but also moves portions of code in command/ and
analysis/featureresponses.py to more appropriate locations. For the
time being it removes the auditory measurement code and vision.py,
since they require some work to make them compatible with the new
system. All plotgroup definitions are moved into plotting/plotgroup.py.
Added GUI option to select color channel in Activity and Weight plots
Reverted to storing timestamps as mpq

Previously comparisons between mpqs was broken on some systems
(e.g. DICE), timestamps were therefore cast to floats. This is unsafe
therefore we are reverting. There was a bug in gmpy that caused
some comparisons to fail, reversing the order of the comparison should
address this problem. If error recurs there needs to be an alternative
fix or a requirement for the latest version of gmpy.
Fixed all GUI tests after changes to plotting of different channels
Merge pull request #535 from ioam/featuremapper

Featuremapper is now a separate project.