Added checking to protect label sets that are being used by active surveys (can't change code, or add or delete entries in these label sets). Added warning to other label sets that are being used by inactive surveys warning about possible problems if changes are made.

git-svn-id: file:///Users/Shitiz/Downloads/lssvn/trunk/unstable@593 b72ed6b6-b9f8-46b5-92b4-906544132732