Fixed 'Bug 5305 - Find Next does not work after switching to a
different window'.
Fixed 'Bug 11205 - Error while getting completion data'.
Fixed 'Bug 11187 - Method order does not match between different
completions '.
Fixed 'Bug 11186 - Ugly Func tooltip'
Fixed 'Bug 5305 - Find Next does not work after switching to a
different window' pt2.
[NUnit] Updated NUnit to 2.6.2.
Updated reference to md-addins
Rename the list variable to have a better name.
Remove duplicates in GetAll methods.

When we build in Wrench, for some unexplained reason, the System
keychain is included twice. This stops us from building the MacInstaller
because we fail to find the correct signing certificate.

The fix is to use HashSet instead of List when iterating through all the
items so that duplicates are not included.
Fix up the return type for GetAll methods.