Flag for cursorline

The commit just adds flag in purpose to handle cursor line behavior.

Some pictures:
Flag is not set
![flag_is_not_set](https://f.cloud.github.com/assets/288446/411673/16482294-ab92-11e2-9a8b-c9387ac997b3.png)

Flag is set
![flag_has_been_set](https://f.cloud.github.com/assets/288446/411674/1d3858d0-ab92-11e2-9696-50e6c3b14b49.png)