Fix bug where email receipt had scientific notation

>>> 40000 / decimal.Decimal("100")
Decimal('400')
>>> 40000 / decimal.Decimal("100.00")
Decimal('4E+2')

This seems to be corrected when saved and pulled
back out of the database, but went ahead and corrected
it across the board.
Update installation.rst

I noticed that you use request.user in some of your templates, which will not work without the request context preprocessor.
Update _cancel_form.html

Fix a small grammar mistake.
Merge pull request #66 from buddylindsey/patch-1

Update _cancel_form.html
Merge pull request #64 from kvnn/patch-2

Update installation.rst with request context processor explanation
2.0b22