Themes: Added truncation to hbs content helper

Fixes #256

- Developed and linked new module, downsize, for tag-safe truncation
- Altered existing content handler to accept options for truncation
- Added tests for handler

Using truncation:

{{content words=10}}
{{content characters=256}}
Adding contributor guide to readme
Merge pull request #341 from cgiffard/text-truncate-helpers

Themes: Added truncation to hbs content helper
Removed my personal information from fixtures as Ghost is starting to get deployed more frequently now for testing purposes.

Don't want random test sites accidentally ranking in search engines for my name.
Fixed word count grammar

Closes #349
- Added utility function to pluralize when appropriate.
Improving the use of paths in Ghost

fixes #392

- adds appRoot, and uses this to calculate other paths
- removes path calculations from loader
- remove the themedir setting in config.. completely unnecessary
- highlights just how important #360 is
Merge pull request #384 from JohnONolan/master

Update fixtures to remove references to me
Merge pull request #388 from gotdibbs/Fixed-word-count-grammar

Fixed word count grammar
Merge pull request #394 from ErisDS/path-rejig

Improving the use of paths in Ghost
fixes extensions bug for image uploader

- extensions set to lowercase
- changed navigation images to hyphenated names and corrected references
Merge pull request #397 from cobbspur/mime

fixes extensions bug for image uploader
Bug Fix: Corrected wrong Keyboard Shortcuts in help modal
Improved several keyboard shortcuts behaviour to more closely match Mou

These include Headings, Lists and inserted dates
Improved modals styling and code formatting

Solves:
* max-height 120px less than height of viewport
* fade-in a dark overlay as well as blur
* animation speeds/transitions should be smoother
* modal sizing fucks up when viewport is resized

Also improves Modal code compliance to Ghost Backbone coding patterns
Passive notifications are dismissed on settings pane change

Closes #342.
It would be totally cool if we could have a Ghost.PubSub so we could hurl events there and pick them up somewhere else. For some reason all the backbone bits work on models, like `trigger` and `listenTo` and `delegateEvents`.
Improved mobile interactions

This is simply a commit which improves the mobile interactions. This does not fix UI problems on mobiles.

New interactions;

Menu
* Swipe right on header to show sidebar
* Swipe left on sidebar to hide

Content
* Tap / Swipe left on item to show preview
* Swipe right to show content list

Settings
* Tap / Swipe left on link to show settings
* Swipe right on settings to show links
Add in CasperJS test to check if Dashboard Widgets are moveable

Requires .time-widget
Merge pull request #378 from javorszky/iss342

Passive notifications are dismissed on settings pane change
Add LiveReload Grunt Dev Task

Adds the ability to run a new task via `grunt dev` that will watch our
sass, templates and javascript files for changes and reload them in the browser.

Also, refactored the Gruntfile to auto load all grunt-* tasks to remove
some code.
Merge pull request #408 from jgable/gruntDev

Add LiveReload Grunt Dev Task