Limit overlays to actual position of error

Currently, any errors on the same line overlap, making it impossible to skip an error and jump to the next one in the line.

Before:
![Before patch](http://imgur.com/3Bw6giE.png)

After:
![After patch](http://imgur.com/QMcg3Rl.png)

This patch fixes this by jumping to the coln given by the error and only marking the error.

![24pullrequests](http://24pullrequests.com/assets/logo-625222452ffc0d57272decb6f851a7fe.png)

Best,
Markus