igcd, ilcm: accept list of integr
Merge master
return 1 if gcd is 1
MatrixBase.is_zero supporting None results.

Extended original implementation of MatrixBase.is_zero to return None if the
matrix may or may not be a zero matrix.  Also found a workaround to issue 4114
to have this method accessible to ImmutableMatrix.

See http://code.google.com/p/sympy/issues/detail?id=4114
Merge pull request #2637 from Tempel/matrix_is_zero

MatrixBase.is_zero supporting None results.
Don't set the doctest encoding

This breaks when sys.__stdout__ is None, which can happen on Windows. It is
not needed anyway because the stdlib doctest already does the same thing.

Fixes #2681. Thanks to Vivek Mohta for the report.
Merge pull request #2388 from shikil/gcd

igcd(*[5, 10, 15])
Bump version to 0.7.4.1
Fix the release script to work with versions like 0.7.4.1
Add newline when updating releases.txt
Make test_pypi work with ints
Merge branch 'master' into 0.7.4.1

Conflicts:
	sympy/__init__.py
Merge pull request #2684 from sympy/0.7.4.1

0.7.4.1
Added links to missing docs in RST file for the diffgeom module
Better docs for Subs.

- Added examples to resolve confusion regarding the result of subs and the limiting value of the expression at that point
- Added examples to clearly show the difference between substitution and numerical evaluation.
- Added `evalf` in the `See Also` of `Subs` documentation section.
minor doc fix
Merge pull request #2688 from Upabjojr/diffgeom_doc

Added links to missing docs in RST file for the diffgeom module
edit fancysets docstrings
Merge pull request #2649 from hargup/fix_subs_doc

Better docs for Subs.
Merge pull request #2674 from smichr/fancy

edit fancysets docstrings