Call simplify() in Add._eval_as_leading_term.  Fix issue 3265.
Extract nested Order expr
Handle NotImplementedError in Pow.nseries
Merge branch 'master' into 3265-eval-lt-fix
remove assert
remove obsoleted stuff in power.py
Add logx defaults
Merge branch 'master' into 3265-eval-lt-fix
Revert "Handle NotImplementedError in Pow.nseries"

This reverts commit 17d61527faa736497b4a2ff37cb6345b93f2a601.
A better handling for rest=0 case
Cleanup prefactor calculation
Merge branch 'logx-clean' into 3265-eval-lt-fix
Hoist constants out of loops.
Added the cbrt function (the principial cube root)
Fix tests for cbrt
Fix cbrt printing
Fix docstring
Matrix pinv: correct XFAILed test.

Addendum to pull request 2571.  One test was marked as XFAIL, so I didn't
notice that it had been set up incorrectly.  Fixed and expanded; whenever
rank-deficient matrices are supported, this test will be ready to go.
Matrix pinv: replace indexing with .pop().

I mistakenly assumed expr.atoms returned a list, when it actually returns a
set.  Therefore, I tried to use indexing to access the one expected item, but
must instead use set.pop().
Mention real_root in docstrings