SF2/VST Title Fixes, Export Dialog Fixes

**SV2/VST Title Fixes**
* Restores auto-name functionality to newly added SoundFont and VST tracks where the track name will take the name of the soundfont or vst plugin, respectively.  This fixes #462 which is a regression bug.
* Tested on Ubuntu 12.04 and does NOT impact the existing .mmpz, .xpf functionality (maintains compatibility with tracks that have a name specified)

**Export Dialog Fixes**
* Parses the (*.wav) or (*.ogg) from the QFileDialog and appends it as a file extension suffix to the exported file name.  This fixes #764, where the export dialog sometimes is missing this information.
* Tested on Ubuntu 12.04 and does NOT impact the Export Tracks option.

**Testing Results (SF2/VST Title Bug)**
Tests were made against `stable-1.1` branch, build 1.0.91.
![screen shot 2014-06-04 at 9 14 24 am](https://cloud.githubusercontent.com/assets/6345473/3173751/a659414e-ebea-11e3-8e61-2683b70ad765.png)

**Testing Results (Export Dialog)**
Tests were made against `stable-1.1` branch, build 1.0.91.
![screen shot 2014-06-04 at 9 15 10 am](https://cloud.githubusercontent.com/assets/6345473/3173760/c5fafb96-ebea-11e3-89a4-b86075e90555.png)


![screen shot 2014-06-04 at 9 15 27 am](https://cloud.githubusercontent.com/assets/6345473/3173761/c97fec0e-ebea-11e3-85ee-139e2592b1ec.png)