Add SlashNewlineStrippingTemplateLoader

This will be the end of long lines in templates!

In a template, you can now end a line with \.  Then the newline is
automagically removed before it is rendered.

NOTE This requires changes to settings.py

Signed-off-by: Bas Westerbaan <bas@westerbaan.name>
Merge pull request #142 from khandhas-infra/template-breaklines

Add SlashNewlineStrippingTemplateLoader