Fix docstring
Fix typo
Merge pull request #2235 from shikil/dpll2

Fix docstring
Merge pull request #2236 from shikil/typo

Fix typo
Change the ipython printing test to use init_printing().

This removes the following deprecation warning while running the tests:

sympy/interactive/tests/test_ipythonprinting.py[1] sympy/utilities/exceptions.py:149:
SymPyDeprecationWarning:

using %load_ext sympy.interactive.ipythonprinting has been deprecated
since SymPy 0.7.3. Use from sympy import init_printing ;
init_printing() instead. See
http://code.google.com/p/sympy/issues/detail?id=3914 for more info.

  warning(see_above, SymPyDeprecationWarning)
.                                                            [OK]
Skip plotting doctest in sympy/geometry/ellipse.py

Fixes issue 3925: Failing doctest in sympy/geometry/ellipse
http://code.google.com/p/sympy/issues/detail?id=3925
Fix cancel() of a Piecewise().

Fixes issue 3923: Calling cancel() on a Piecewise() instance.
http://code.google.com/p/sympy/issues/detail?id=3923
Merge pull request #2244 from jrioux/piecewise

Fix cancel() of a Piecewise().
Merge pull request #2246 from jrioux/interactive

Skip plotting doctest and avoid deprecation warning.
Added WIP frame file
Added functions map_variables, removed __new__
Coded initialiser and time_derivative methods
Added auxiliary functions file, added convert_pos_vector function
Added new initialiser, changed tree implementation
Changed tree implementation to avoid tranversing entire tree
Added support for tuple args, recitified trans methods
Rectified mistakes in code
Added docs, finalised functions and removed unnecessary reexpressions