OS X Support

The os x installation and running now fully works.

Have tested:

* successful install
* quitting an install mid-way through (we could enhance this by deleting the application bundle in ~/Applications?)
* opening multiple builders from the website

This branch has allowed us to:

* remove the need for applescript (yay!)
* have native python that listens for osx url/file events
* have consistent icons (including windows/linux)
* not have to spawn a seperate jinn in order to service a new url request
* have consistent proxy support by removing the dependency on the python requests library

Other changes:

* isInstalled() now looks for the manifest
* this fixes 120 - where a partial install would have thought to have been completed
* fixes return values not being passed back from install/update/etc.
* moves the jinn executable into the Resources folder
* fixes launch services update of application
* fixes error messaging on copy fail

We will need to:

* update the other manifests to include the icon image
* potentially have a different icon for the spawned shell instances in the dock as they don't group together(?), OR wrap them in their own app bundle