Make Indexed and IndexedBase commutative by default.
Adds test for .coeff() on Indexed instances
Update tests to match new order of arguments.
Updates docstrings to match new order of arguments.
Updates docstrings to match new order of arguments.
Fix a bug in coeff for Mul
The coeff method for Mul was returning 2 for expression 2*x when n=0. fixes https://github.com/sympy/sympy/issues/7377
Merge pull request #7378 from debugger22/expr_coeff_fix

Fix a bug in coeff for Mul
Merge pull request #7355 from bjodah/fix_coeff_for_Indexed

Fix coeff for indexed

Fixes #5758.
Merge remote-tracking branch 'upstream/master' into finite_difference
Fixed/updated docstrings with new master