Fix heuristics for real, bounded symbols, for example: limit(r*sin(1/r), r, 0)
More cleanup in heuristics()
Fix fact extraction from composite assumptions.

_extract_facts is only passed expressions in CNF and returns None
when it can't find a meaningful fact to extract.

This is enough to guarantee a correct handling of all possible forms of
assumptions and allows the following to work correctly:

    assert ask(Q.real(x), Q.real(x) & Q.real(y)) is True
    assert ask(Q.real(x), Q.real(x) | Q.real(y)) is None
    assert ask(Q.real(x), ~(Q.real(x) >> Q.real(y))) is True
Fix tests for composite assumptions, add new ones in test_assumptions_2.py/test_query.py
Fix typo
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