• add vpp filter to sharpen edges and details. (--vpp-unsharp)
• add another vpp filter to sharpen mostly edges avoiding overshoot. (--vpp-edgelevel)
• now NVEncC will automatically select suitable GPU device to run on, in multi GPU environment.
• fix issue that crop was doubled when using crop & resize together ( #13 ).
• change "--transfer" flag names as they are in other software such as x264 ( #14 ).
  smpte-st-2048 → smpte2048
  smpte-st-428 → smpte428