DOC: updated robot_continuous.py tutorial + some rearrangement
DOC:small corrections in tutorial
Merge branch 'master' into graphics
TRIV: typo
format get_input docstring in epydoc
correct confusing exception mentioning old post_single
interface get_input to AbstractSysDyn
convert to new-style classes

affected classes:
	- Polytope
	- Region
	- LtiSysDyn
	- PwaSysDyn
	- HybridSysDyn
	- AbstractSysDyn

among others, this change avoids type() returning:
	<type 'instance'>
instead of the actual class name
check if Iterable provided to createLM

intead of using isinstance to check for Polytope.
This avoids type mismatch caused when the polytope module is reloaded.
An example is running robot_continuous.py in an IPython session,
then running another file that calls get_input.

Also, in get_input: pythonic iteration over target Region's polytopes
rename get_cell_id -> find_discrete_state, and refactor it
update abstract.__init__
example use of get_input, for developers
docstrings and style
variable renaming
shorter function names: solve_feasible_open_loop -> solve_open_loop, solve_feasible_closed_loop -> solve_closed_loop
solve_closed_loop: further variable renaming, add docstring
solve_closed_loop: return when target polytope becomes empty

The previous version returned as soon as s0 became empty, if not using all the horizon.

This change adds the case that all the horizon is used, and both s0 and p2 are empty. Since the union s0 \cup p2 is recursively taken, this is possible if p2 is initialized empty. This is possible only by passing an empty P2 as argument.
extract union_or_chain from solve_closed_loop
last closed-loop iteration in for-loop, not separate
rename variables, fix keyword arg preceding non-kw arg