Linearizer class now works with LagrangesMethod

Generalized the Linearizer class to work in the presence of
lagrange multipliers. This required the following changes:

- Modification to LagrangesMethod initialization to input
the holonomic and nonholonomic constraints separately. This is
different than the previous way of inputting all constraints in
`coneqs`, with the holonomic constraints time differentiated.

- Reformulation of the general Linearizer form. This changed the
`Linearizer` class methods internally, but not the interface.

- Pulled _find_dynamicsymbols method from KanesMethod to the
functions.py file, as it is used by both LagrangesMethod and
KanesMethod now.
Merge branch 'LinearizeClass' into LinearizeLagrange

Conflicts:
	sympy/physics/mechanics/linearize.py
Added `solve_multipliers` to LagrangesMethod

Added a function to solve for the value of the multipliers at a
given operating point. Returns either a dict of {symbol: value}
(default), or a column matrix of the solutions. Also added a test
case that has constraints to test this method.
Merge branch 'LinearizeClass' into LagrangeImprove

Conflicts:
	sympy/physics/mechanics/functions.py
	sympy/physics/mechanics/kane.py
	sympy/physics/mechanics/linearize.py
	sympy/physics/mechanics/tests/test_linearize.py
Added `linearize` method for LagrangesMethod

Created `linearize` class method for LagrangesMethod class.
Merge branch 'master' into LagrangeMerge
Added deprecation warning to LagrangesMethod

Added a deprecation warning to LagrangesMethod for the new interface of
hol_coneqs and nonhol_coneqs. Updated tests to reflect change.

Also added rolling disc test for lagrange.
Merge remote-tracking branch 'upstream/master' into LinearizeLagrange
Merge pull request #7681 from jcrist/LinearizeLagrange

[WIP] Linearize lagrange