Improve button styles

I noticed a couple of buttons don't match the newer styles.

## Issue edit note form

### Current (cancel button is big)

![Screen_Shot_2016-01-08_at_2.18.29_PM](/uploads/c7928e6644e886090f55cb61076c9e89/Screen_Shot_2016-01-08_at_2.18.29_PM.png)

### Now

![Screen_Shot_2016-01-08_at_2.18.22_PM](/uploads/d15c3c458a08ce5a59c367c7fb379c31/Screen_Shot_2016-01-08_at_2.18.22_PM.png)

## Merge request code discussion

### Current

![Screen_Shot_2016-01-08_at_2.21.37_PM](/uploads/b970ff3e5d9ef5e62f83bb56d5505f8d/Screen_Shot_2016-01-08_at_2.21.37_PM.png)

### Now (Also changed to `btn-save` class which changes to green. This matches everything else)

![Screen_Shot_2016-01-08_at_2.22.01_PM](/uploads/ed520de72177de92efe21d236bb04d24/Screen_Shot_2016-01-08_at_2.22.01_PM.png)

cc/ @jschatz1 @skyruler @creamzy 

See merge request !2350