Make toolbar formats dropdown configurable via system setting

Title already says it all =)...this enhancement makes it possible to configure the formats dropdown list in the toolbar:

![bildschirmfoto 2014-08-25 um 16 38 23](https://cloud.githubusercontent.com/assets/445501/4031278/933ada26-2c65-11e4-897c-9c2c600ea6bc.png)