Drop obsoleted comment about with statement in risch.py (closes issue 3665)
Preprocess user input for rsolve to allow linear recurrences in a more generic form (e.g. y(n) + a*(y(n + 1) + y(n - 1))
Issue 2187:IntQubit to work with inner products
Fix issue 3565

    1) for |a| or |b| = oo: handle the case of geometic series
       with eval_sum_hyper()
    2) in doit(): work arround the case when eval_sum returns
       partially evaluated sum with Piecewise
Remove ancient, commented out, code from Sum.doit()

    This fragment is in place long time
    ago (commit 157dd374e728e37eebef729584cd9e94fad02bc8,
    issue 577) for no reason.
Merge pull request #1900 from amitjamadagni/innerproduct

Issue 2187:IntQubit to work with inner products
Merge pull request #1904 from skirpichev/misc

issues 3565 and 3665; preprocess rsolve input
doctest blacklist dependency check

before blacklisting files check that their dependencies are not met

this PR 'unskips' a single doctest of the preview() function which does
not spawn a viewer
'py' is required for the doctests in conftest.py
partly fixes LaTeX doctest problem in galgebra/latex_ex
use import_module to check for dependencies
dependency check for doctests via a decorator
temporarily blacklist latex_ex until Issue 3969 is resolved
use @depends_on instead of blacklisting the preview.py doctest
use @depends_on in autowrap.py to check for f2py
create dummy executable to doctest functions which spawn a viewer
removed unused imports from preview.py
Monkey-patch pyglet for doctesting
doctest: module docstring dependency check support
add support for doctesting the plotting/pygletplot module