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.
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