imageset improvments:

    1) canonicalize transformation from the input
       to be Lambda
    2) if _eval_imageset wasn't able to compute
       image - we return an unevaluated ImageSet object
Add imageset to sphinx docs
Inequalities: return BooleanAtoms instead of bools.

Extension of a similar change to Relational objects.  Now any usage of <, <=,
>, or >= will result in a BooleanAtom (S.true or S.false) being returned.
To handle this, many pieces of code were changed so they no longer expect True
or False; some downstream code may need similar treatment.
Added kwarg in lambdify to support return of numpy array instead of matrix in a more user friendly way
forgot to clean trailing whitespace
Merge branch 'master' of https://github.com/sympy/sympy
Changed test_numpy_matrix to use numpy.testing.assert_allclose
Edited doc string for lambdify. Pep 8 formatting fixes.
Fixed numpy lambdify test to check return type

Now ensures use_array=True returns numpy.ndarray, and
use_array=False returns numpy.matrix.
Fixed test error in test_lambdify
Merge pull request #2907 from skirpichev/imageset-uneval

imageset() improvements
Merge pull request #2987 from jcrist/master

Added support for kwarg "use_array" in lambdify (fixes  #2931)
Merge pull request #2984 from Tempel/number_ineq_STrue

Inequalities: return BooleanAtoms instead of bools.
Update Rajat Aggarwal's name in AUTHORS/aboutus/.mailmap