Add netcam_params and netcam_high_params options.
Allow user specification of any additional options to netcams.
Implement a standard set of routines for parsing parameters provided for both video devices and netcams.
Revise option names for consistency
vid_control_params => video_params
mmalcam_control_params => mmalcam_params
videodevice => video_device
tunerdevice => tuner_device
netcam_highres => netcam_high_url
Conversion to use video_params for the following:
v4l2_palette => video_params option of palette
input => video_params option of input
frequency => video_params option of frequency
norm => video_params option of norm
Conversion to use netcam_params for the following:
netcam_rate => netcam_params option of capture_rate
netcam_decoder => netcam_params option of decoder
netcam_use_tcp => netcam_params option of rtsp_transport
netcam_proxy => netcam_params option of proxy
netcam_keepalive => netcam_params option of keepalive
netcam_tolerant_check => netcam_params option of tolerant_check
Closes#927
