fixing cap_pvpapi interface and making sure both AVT Manta and Proscilla
series are supported. Testing this with both cams for Windows and Linux
exhaustively.

Optimizing memory footprint by removing unused calls.

Adapted with the input of Shai

Added small example that illustrates how it should work.
Merge pull request #3322 from StevenPuttemans:fix_pvpapi_interface