NCBC-165: Provide support for view does not exist scenarios

Currently, when a view doesn't exist an InvalidOperationException
bubbles up to the caller.  New approach provides CheckExists method
of view, which may be called prior to iterating over view or new
typed exceptions which provide details of the error.

Change-Id: Iedec5543e3eb096815fcbd77a764675d8ed5fded
Reviewed-on: http://review.couchbase.org/24068
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Reviewed-by: Saakshi Manocha <saakshi.manocha@globallogic.com>
Tested-by: Saakshi Manocha <saakshi.manocha@globallogic.com>