plot functions now pass on kwargs when constructing series.
gh2666: terms_gcd does not remove and _keep_coeff doesn't hold 1.0

In addition, if only a 1 (or 1.0) is extracted, the original
expression is returned from terms_gcd rather than the polys-modified
form (e.g. 2.0*x + 3 instead of 2.0*x + 3.0).
Solvers: removed duplicate output

Fixes issue 4129 by passing result through set before returning
Corrected position of ordered and set tomaintain canonical ordered list
Added test cases for issue 4129
Removed redundant test cases
fix generate_bell with recursive algorithm

TODO: replace with a non-recursive algorithm.
keep 1.0 and -1.0 with _keep_coeff
Merge pull request #2689 from smichr/gh2666

gh2666: terms_gcd does not remove 1.0
use non-recursive algorithm for generate_bell
Merge pull request #2690 from avichaldayal/4129_multiple

Solvers: removed duplicate output
Merge pull request #2668 from paul-scott/plotkwargs

plot functions now pass on kwargs when constructing series.
Add Avichal Dayal to AUTHORS/aboutus. Welcome to SymPy!
Add Paul Scott to AUTHORS/aboutus. Welcome to SymPy!
edit simplify_logic docstring
indent discussion of parameters
Merge pull request #2698 from smichr/edit

edit simplify_logic docstring
Merge pull request #2699 from smichr/auth

add authors
Merge pull request #2694 from smichr/bell

fix generate_bell
check for break condition earlier in generate_bell