A new title and a scrollbar are added

When mouse hovers on lock icon, initially it used to show "Edit Note", I changed it to "Preview Note". 

![editnote](https://cloud.githubusercontent.com/assets/6604116/3789945/0cf79c70-1ad5-11e4-8d6c-1ec3c80acb44.png)

![previewnote](https://cloud.githubusercontent.com/assets/6604116/3789944/0cf6313c-1ad5-11e4-8e39-dc980dcf35f9.png)

Solved issue #161. Now, scroll bars appear when they are needed. 
![scrollbar](https://cloud.githubusercontent.com/assets/6604116/3789942/0cf09e98-1ad5-11e4-8f1f-c67c71c2584c.png)

![noscrollbar](https://cloud.githubusercontent.com/assets/6604116/3789943/0cf0c22e-1ad5-11e4-8aba-1a165c0e1479.png)