Added new functionality

* Refactored code to pass linting
* Introducted getContext() and getPreviousContext() convenience methods
to retrieve mediaquery state
* Added ability to fire callbacks when a mediaquery unmatches
Minified File
Modified to allow unmatch to work with contexts

Modified the callback firing functionality to work with mediaquery
context 'unmatch'
Added minified file
Fixed addQuery issue introduced by match/unmatch
Fixed attachEvent typo
Merge pull request #11 from patocallaghan/master

Added ability to fire callbacks on exiting breakpoints
Update README.md

Updated documentation to reflect new match/unmatch syntax.
Update README.md
Fixed demo issues

Fixed up demo to use proper 'match' signature
Updated demo
Fixed an error in older versions of FF

getComputedStyle threw a javascript error in older versions of Firefox because the second parameter wasn't included. More info here: http://caniuse.com/#search=getComputedStyle

Signed-off-by: Wout Mager <wtswout@gmail.com>
Merge pull request #15 from patocallaghan/dev

Fixed Demo Issues
Merge pull request #16 from Eworm/master

I made a fix for older Firefox versions
Update onmediaquery.min.js

Minified latest pull request and added minified title block.
fix