Add more EventInstance bindings

[IzaZed]

Add these bindings (and python properties where appropriate) to EventInstance:

• getCPUUsage
• getPitch
• setPitch
• getReverbLevel
• setReverbLevel
• Release
• getTimelinePosition
• setTimelinePosition
• getVolume
• setVolume
• isVirtual

[tyrylu]

Why do you think having the get|set methods and the properties at the same time is beneficiary? Also, I know, I don't like it myself, but adding tests would be helpful as well.

[IzaZed]

ah, that was just for API completion, only using properties works just as well for me though
I'll remove the methods and add tests

[tyrylu]

Thank you.