Appcenter Juno Release for 1.1.0

Changes for the following:
*Right click a selected word and look up its meaning using a online dictionary
*Added a preference option to customize highlight colour

Fixes:
*Prevent Bookworm from opening links like http, ftp etc and use the default browser to open the same
*Fixed an issue where the lines overlapped for the first couple of pages in the book
*Use of GResource to speed up loading of icons, scripts, etc.
*Some minor CSS compatibility with Juno