Added Saplo API wrapper

All Saplo API calls now go though a javascript wrapper layer to improve
readability of the code. This also improves error handling and decreases number
of Saplo API calls we need to make.

As an effect of this we now return Url.id as response to 'tagga' so a similar
change needs to be deployed in scrape.js and the webbackend.
Move around stuff in .gitignore

Place all gitignore rules in the topmost directory
Add tag booster

SInce saplo sometimes misses tags we do our own analysis of the text and pull
out some known tags that we have registered.

Also includes underscore 1.6.0
Seems like Parse uses underscore 1.4 which doesn't support the indexBy function.
Use snowball.js for stemming.

Stemming is the process of removing suffixes from words to get the 'stem' when
for instance matching words. This allows us to map all different versions of
e.g. socialdemokraterna (socialdemokraternas, socialdemokratisk, socialdemokrat, ...) with one rule.
Add 'term' when creating boost tags.

Add a way to match other words than the tag itself to a tag. For instance we
can match '(s)' to 'socialdemokraterna'.
Add background job for updating UserTags.

This is a first step towards using the tag relations when generating statistics.
User topic tag generation

Add a background job that can create user topic tags. By doing this we can
propagate tag dependencies in the backend database.
Add support for guessing topic on an Url object.

Disable for now since saplo has not been trained properly yet.