Fixed cnetextract to properly delete edit locked points and measures from the...

Fixed cnetextract to properly delete edit locked points and measures from the network when filtering them out by removing their edit locked state.  Consequently, this change fixes #188, but the internals of the program should be reworked later to not necessitate working around edit lock in this matter.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2821 41f8697f-d340-4b68-9986-7bafba869bb8