Halo notes

Halo Notes it's the start of something new called Extensions, until now Halo))) had the option to open an App and even a specific Activity of an App but now brings the opportunity to show more information. This pull request adds up to four notes to your Halo (more than four could be annoying) but it’s being made to allow other developers to add more information to your Halo like the Time (Hours and Minutes), the battery percentage or even the CPU speed. But for now only some notes!
Suggestions and WIP:
-	I use a void inside MainActivity, so it doesn’t loads at boot, because I didn’t want to mess with your appreciated BootReceiver.
-	Inside the Extensions, you can’t see in the summary the text written inside the note, but it’s highly recommended. 
-	Also to apply the notifications after writing them to the SharedPreferences, you need to restart the app because I load everything at the onCreate but can be arranged with a couple of tricks.
That’s all folks!