..pvmanager.widgets: adding VTable support for service arguments and
results.

Change-Id: I5a3dcdb393a3bae23a4a011d88248ead25e9138a
Signed-off-by: Kunal Shroff <shroffk@bnl.gov>
..service.channelfinder: prototype for pvmanager channelfinder
service.

Change-Id: Idd3ff2443d73fd65ef352535feeae4faa256d347
Signed-off-by: Kunal Shroff <shroffk@bnl.gov>
..service.channelfinder: adding missing display for properties
and tag. channels sorted by name

Change-Id: I830ece3aeb08f794e632f1a6289eeaa35522980a
Signed-off-by: Kunal Shroff <shroffk@bnl.gov>