Browse tags and their relations while filtering questions [feature/tag-browser]

# A controversial feature

## Architecture

* Collection view will hold all the tags (initially all tags ordered by occurance)
* Footer will show number of questions matching selected tags
* Header will contain search bar holding filter-phrase in text form
* The tag-browser will allow browsing a tag's relation in a n-1-only fashion as such we will not limit the relations to the whole set of pre made selections but only to the last selected one.

## Interaction

* Tags in collection view will be reloaded with new tags upon a single tap on any tag on screen
* Search bar holds tags which can be added as filter (as in questions view) by double tapping on a tag
* The footer will contain a view indicating the number of questions still matching the current filter (selected tags in conjunction), tapping will load the questions view with filter
* Navigating through the screens shall be enabled by swiping on the main view

## UI mockup

<a href="https://raw.github.com/opfo/resources/master/Mockups/Exports/Tag-Browser-View-20130506T2131.png"><img alt="The Tag-Browser" width="320px" src="https://raw.github.com/opfo/resources/master/Mockups/Exports/Tag-Browser-View-20130506T2131.png"></a>

## Tasks

- [x] Add item to tabbed-bar loading the collection view
- [x] Setup boilerplate code for collection view
- [ ] Load tags as collection view cells
- [ ] Size tags by occurrence, reflecting their order relatively 
- [ ] Bind tap/double tag-events and reload data with related tags
- [ ] Enable swiping through previously made selections
- [ ] Setup footer, refresh matched questions and load questions view
- [ ] Do some crazy animation stuff
- [ ] Reflect selections made in search bar as string in common tag-notation ([css3] [html4])
- [ ] Get some sleep

That'll be all folks...