typedesc: Removed VEC7 size printing (on Larry's recommendation)
Added SMPTE classes for easy conversion
DPX: Added smpte:KeyCode and smpte:TimeCode attribute handling
EXR input: Fixed box attribute casting. Added smpte:KeyCode and smpte:TimeCode attribute handling
EXR output: Fixed arraylen handling. Added smpte:KeyCode and smpte:TimeCode attribute handling