Conditional syntax highlighting, no longer to seperate
	filters.  Filter is now dependent on env. type.
Cleaned up get_lines filter
filterOutLatex replaced with built in 'escape_tex' filter
	(see template.py)
Added explicit filters.
Sphinx specific metadata now stored in _draft namespace.
Added a nice comment to explain the line splitting.
Re-arrange imports, added some comments, general cleaning.
Added region headers, to help visually separate elements
of the template.
Centeralized all "nbconvert sphinx block" logic (macros)
Added more comments and header comments.
Make sure we dont stomp all over an existing _draft key, value.
Fixed, wrong Sphinx block specifiers used.
Localized code into jinja macros.
Fixed, backwards defaults.
Fixed, global var interferring with locals vars
Changed rule attachment logic.
	Instead of the horizantal rule following the target via a
	minipage, the needspace package is used.  This frees the
	need to preprocess the target block using the
	sphinxtransformer.  This allows us to rely on Jinja more,
	as intended by nbconvert.

Fixed some macro names to stay PEP8 consistent.
Removed an unnecessary comment.
Unified the output type blocks into the render_output macro.
Updated comments
Centeralized some code into methods
Added more comments
Changed maximum line length from 87 to 85 char.
Fixed string conatation with int value in Jinja.
Fixed single backslash breaking Jinja string output.
Removed unnecessary wrapping by listings package.