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
Add numeric computation doc page

Discusses lambdify, ufuncify, and Theano options for numeric evaluation
add link to numeric computation in modules index
replace x.length with n
add evalf
Merge branch 'master' into 2085-bounded-x-limit
Merge branch 'master' into pr343-fix

Conflicts:
	sympy/assumptions/tests/test_query.py
The minimal polynomial of products of rational powers of integers are
computed much faster in some cases.

In master

``minimal_polynomial(nsimplify(pi, tolerance=0.000000001))``

hangs (see #2234 and issue 4014)

Now it takes a fraction of a second.
added missing import
Blacklist numeric-computation.rst tests if numpy or theano modules are not imported
Fix tests in numeric-computation.rst
Install numpy for numeric-computation.rst if TEST_THEANO is true
Merge pull request #13 from skirpichev/mrocklin-computation-docs

fix travis failures
Fix sphinx test in travis: drop evalf-label
Install scipy in travis (TEST_THEANO) for numeric-computation.rst
Fix trailing whitespaces and reformat long lines