Renamed some global actions
Reworked LivestreamerController so that it can handle multiple streams

Watching multiple streams simultaneously still WIP.
Added different button types to ModalController and changed how the click action works.
Implemented basic concept of watching multiple streams

- Added button for closing the "now watching" dialog.
- Added button to titlebar indicating the current number of running streams. Will later be used to navigate between the opened streams.
- Closing the application while having streams opened now opens a confirmation dialog.
Let the livestreamer child process spawn in detached mode
Implemented the watching route

Opened streams are now being listed by clicking on the button in the titlebar.
Increased the livestreamer validation timeout
Fixed various middle click bugs
Added stream types to settings... see #16
Fixed form and settings stylesheets
Added application icon

Will be used by windows as the taskbar icon, etc. The icon for the .exe file still needs to be added. Grunt-node-webkit-builder currently produces ugly downsampled icons, so we need to wait for a fix first.
Implemented minimize to tray feature. resolves #16

Disabled for OSX+Linux. Tray icon is empty on these platforms.
Show better error messages
Split up the release grunt task
Fixed infinitescroll button showing up when there's nothing more to fetch
Fixed error message for older livestreamer versions
Added settings for automatically hiding the stream popup
Added refresh button to titlebar which reloads the current subroute's model
Added animation to searchbar dropdown
Removed not-allowed cursor for disabled links and buttons
Added livestreamer documentation links to settings

Also changed some texts and styles