Sort out README.md
Sort out README.md

* Remove in-complete list of examples and direct people to the [example explorer](http://tombatossals.github.io/angular-leaflet-directive/examples/0000-viewer.html). Now it's easy to miss because of the list and hard to notice that list was very incomplete. If you think the list should be there, I can divide it to subcategories and add the missing stuff.
* Fixed indentation and code style from code examples
* Correct LeafletJS address
* Clean up and shorten other texts for better readability. Because life's too short to waste reading long docs. ;-)
* Move Gitter badge and primary description up
* Line up coverage etc badges to take less space
realtymaps/ui-leaflet,simplot/angular-leaflet,angular-ui/ui-leaflet,tombatossals/angular-leaflet-directive,abdelrahmansaeedhassan/FirstTest,realtymaps/ui-leaflet,joelrahman/angular-leaflet-directive,arkhemlol/angular-leaflet-directive,elesdoar/angular-leaflet-directive,vincent-ollivier-everysens/everysens-ui-leaflet,angular-ui/ui-leaflet