Support VST transport messages

[diplojocus]

play, pause, position etc...

[Simon-L]

Usages include:

• Syncing to host tempo
• Sequencing according to "musical position"

The call should be AudioEffectX::getTimeInfo() and returns a VstTimeInfo object. For reference, as the VST documentation isn't officially publicly accessible: VstTimeInfo struct: http://www.dith.it/listing/vst_stuff/vstsdk2.4/doc/html/struct_vst_time_info.html getTimeInfo(): http://www.dith.it/listing/vst_stuff/vstsdk2.4/doc/html/class_audio_effect_x.html#321316fdaf0c636a8db927eabe8b5304

For reference also, an example usage: https://gist.github.com/gaspard/6448474#file-gistfile1-cpp-L106