Implement known values of Si, Ci, Shi, Chi at oo and -oo
Tests for values of Si, Ci, Shi, Chi at oo and -oo
Replace 0 by S.Zero
add subfactorial function
tweak docstring eqns
Merge pull request #1692 from smichr/subfact

add subfactorial function
added test for http://code.google.com/p/sympy/issues/detail?id=3029
Add Fresnel functions to the docs
putting the test into the appropriate file
Merge pull request #1662 from raoulb/fix_issue_3503

Fix issue 3503
Merge pull request #1705 from raoulb/fresnel_doc

Add Fresnel functions to the docs

Merging this now.

I eventually plan to improve the sections of the "special" functions page after the new "erf*" functions are in.
implemented symbols('aa:z')
added test for new symbols feature
removed trailing whitespace
fixed the unicode fix
fixed symbols issues
removed trailing space
emulating string.letters for py3
moved tests to appropriate files
forgot to include Or