gst: add wrapper for deinit function (tinyzimmer#15)

* gst: add wrapper for deinit function

* build: prevent unused variable warning in cgo code compilation.

While compiling the code gcc complained with unused-variable
According to:
golang/go#6883 (comment)
Wall flag should not be used in CGO, nonetheless in this PR we only
remove the unused variable warning.

Co-authored-by: Solganik Alexander <alexanders@anyvision.co>

bin: allow bin creation from elements string. (tinyzimmer#13)

Adding golang binding for gst_parse_bin_from_description gstreamer API

Co-authored-by: Solganik Alexander <alexanders@anyvision.co>

Modified gst_pad.go c function cgoGstPadActivateModeFunction (tinyzim…

…mer#12)

Modified to call goGstPadActivateModeFunction instead of cgoGstPadActivateModeFunction which would be itself.

use internal gstClockTimeNone for comparissons

more logging helpers

bump glib version

add remove pad

add another error helper for elements

more element and pad fixes

bump go.mod to 1.16 - some query parsing fixes