new: __le__, __ge__ of Polytope, Region

and polytope.polytope.is_subset
define ABS_TOL in polytope
new: is_feasible in abstract.feasible
bugfix: plot discrete vector field
new: simplices2polytopes in polytope
new method: distance, of Polytope, Region

to implicitly quantify proximity of given points to boundary
more logging in polytope.polytope
Merge branch 'master' into disc
refactor HybridSysDyn and test it

env_labels, disc_sys_labels become explicit arguments to HybridSysDyn.__init__.

env_labels, disc_sys_labels are now properties, so protected from changing.

If no env_labels or disc_sys_labels are provided, then they default to ints, with warning. The ints are not saved, but instead returned using range upon access.

If the number of mode labels does not match disc_domain_size, or len() is undefined for them, then again the default ints are used.

The previous version defined labels as given, even if they didn't match the dynamics keys, in which case ints were compared to dynamics keys.

- logging messages
- docstr restructured
allow for missing mode combinations in HybridSysDyn
warn if missing env,sys mode combinations in HybridSysDyn
check each HybridSysDyn mode has PwaSysDyn dynamics
new: HybridSysDyn.__repr__
new: PwaSysDyn.__repr__
bugfix: check_convex when taking union in discretize

introduced in 0def035a65b0409865440449c97d463a3061f348
Merge branch 'master' into disc

Conflicts:
	tulip/abstract/discretization.py
messages, use Wset.chebR, dpi for discretization snapshots
rm synth.states2bools
bugfix: avoid overwriting statevar argument

Initially function fts2spec was used only for the system FTS.
So statevar was set to 'loc' inside fts2spec.
The it was used also for the environment FTS.
So statevar became a keyword argument, so that it can be changed to 'eloc', for the env FTS.
However setting statevar to 'loc' inside fts2spec remained, overwriting 'eloc' with 'loc' in the case of an environment TS.
replace operator -> by !, || in mutex

to enable evaluation of initial condition that includes mutex