summary.py: Simplify the way HTMLIndex works

Basically this patch replaces the returnList() function with
os.path.relpath(), which can be used to return essentially the same
output.

Signed-off-by: Dylan Baker <baker.dylan.c@gmail.com>
Completely replace HTMLIndex class

This patch removes the need for the HTMLIndex class by reimplementing it
directly in the mako template. This results in a slight amount of
overhead on a clean run (since mako generates python from it's
templates), but removes the need for an entire class that only added a
layer of abstraction to the process.

Signed-off-by: Dylan Baker <baker.dylan.c@gmail.com>
Rename mako templates in format <name>.<extension>.mako

I.e: 	renamed:    index.mako -> index.html.mako

This should make it a little easier for someone looking through the code
to understand what these templates are for.