Changed __add__ to return the correct phase for the addition of two TWave objects
change warning flag to warn in line with code
test non-linear equations in _solve_system
cache autowrap
fixed docstring tests
Fix the MathJax CDN

The old CDN gives 404. We also need to go in the docs repo and retroactively
fix all built docs there.

Fixes #7983.
change docstring to reflect preference for tuples over lists
test_code_quality shows no errors
manually revert 4346424be94ff3e0a4a4fbfc5a6f35a3a0009d5a
fix tests for zero=True symbols
Merge pull request #7978 from pbrady/cacheit_autowrap

cache autowrap
Merge pull request #7952 from cstoudt/master

[issue #7944] Changed __add__ to return the correct phase for the addition of two TWav...
Merge pull request #7984 from asmeurer/mathjax

Fix the MathJax CDN
Merge pull request #7988 from smichr/zero

manually revert 4346424be94ff3e0a4a4fbfc5a6f35a3a0009d5a
Merge pull request #7966 from smichr/2777

2777: check nonlinear systems
define Add._eval_is_zero when Add is noncommutative

Also, delete the is_commutative definition since this is handled
at creation in operations.py
Relational: add tests for `Eq(p, 0)` where p is positive and similar

Interesting the `Eq(p*I, 0)` ones pass, the real others are XFAIL'd.
Equality: less automatic simplification, fix 'Eq(p, 0)' for p positive

Stop using the `_eval_sides` code in `Equality.__new__`.  Instead put
simpler code directly in `Equality.__new__`.  Drop the heavy
`dif.equals(0)` and replace it with `dif.is_zero`.
Left the .equals(0) stuff commented out for now.

This also fixes `Eq(p, 0)` returning unevaluated when
`p = Symbol('p', positive=True)`.  Now it returns S.false.
Equality: unXFAIL the Eq(p, 0) is S.false test
Equality: use is_zero test only when is_complex is True

Prevents failures with noncommutative symbols.  Add test.