change --no-cache to --force, fix implementation
pointless commit so Travis will run
Merge pull request #149 from duckduckgo/zaahir/fix-no-cache

change --no-cache to --force, fix implementation
Server: deal better with changing page structure.

This is still far too tied to a particular page layout, but it won't die
now.

Fixes #151.  (With improvements to come)
Server: clean up file cache loading somewhat.

This makes a more straight-forward path through the code to understand
what is happening.

Also more commenting on the files themselves, to make it easier to
review in-browser.