clean code for a better PR, adding title and scrolling support

please do not consider preview PRs, the code was a bit confusing.
I'm including here all the features I've added with more comments and
a cleaner code so you can easily take a look at changes and choose what you wanna pick:

 - title support (double click to change the title, you can still move the window with drag&drop on title)
 - scroll bar support (I really needed this, my notes are always so loooong :P)
 - link support (this was life changing to me)
 - markdown support

![stickynotes](https://cloud.githubusercontent.com/assets/504700/5423787/bce5f44e-82cf-11e4-8b63-957b6b5f646d.png)

thank you for this piece of software ;)