Add an option to disable find all references
Make XmlDocFilter asynchronous

And remove name union fields which aren't available in F# 3.0.
Merge pull request #360 from dungpa/async-xmldoc

Make XmlDocFilter asynchronous
Merge pull request #359 from dungpa/disabling-option

Add an option to disable find all references
Merge remote-tracking branch 'upstream/master'