Improve 'Implement interface'
Bring in the latest round of bug fixes from VFPT.
* No longer regenerates already implemented members
* No longer generates extra members for events

This also includes recent VFPT refactorings for easier diffing in the future
Merge pull request #582 from rojepp/impl_interface_fixes

Improve 'Implement interface'
Make FSharp.Targets search case insensitive
Merge pull request #584 from rneatherway/issue583

Make FSharp.Targets search case insensitive
Updated to FCS v54
Merge pull request #586 from 7sharp9/fcsupdate

Updated to FCS v54