SF2/VST Title Fixes, Export Dialog Fixes

[tresf]

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 VST/SF2 Title Bug #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 Export as ".wav" does not append extension #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.

Testing Results (Export Dialog)
Tests were made against stable-1.1 branch, build 1.0.91.

[tobydox]

Thanks for all the work and improvements!