Build 404 pages from the theme if they exist
Add a 404 page to the MkDocs theme.

This change involved breaking up the context generation to create a sub
context that can be used for rendering pages not based on a specific
Markdown file.
Minor updates after feedback
Merge pull request #194 from d0ugal/404

Build 404 pages from the theme if they exist
Fix: use underscores in google_analytics
Merge pull request #219 from ngzhian/fix216/ga-underscores

Fix: use underscores in google_analytics
Add MANIFEST.in file

The MANIFEST.in file includes all of the files used by the themes we
ship with MkDocs and excludes __pycache__ (py3) and py[co] (py2).

Fixes #196
ignore IDE settings
Added generation of searchindex for pages
Added generation for sections h1 and h2

Did not give any decent search results without index on section level.
Documentation
Added generation of searchindex for pages
Fix PEP8 formatting issues.
Remove editor specific ignores
Simplify the compat module
Initial draft of working Tipuesearch