Ensure framework version is considered, rather than hard-coding to 4.0
Updated for F# 3.1 and .Net 4.5 framework versions
Ensure framework version is considered in ResoverProvider
bump version and remove 3second pause
Merge pull request #317 from 7sharp9/FSharp.Core-fix

FSharp.core fixes #313
Implemented last window caching with a single instance of the tooltip window

Also added a failsafe on displaying empty tooltips
Cached last tooltiptext
Cleaned up the code slightly
Switched to mutable rather then ref
Merge pull request #320 from 7sharp9/186

Fix for #186