stop tryGetDoc returning Some(null) causing an exception
Added the ability to create a DataTipText to the compiler wrapper.  This allows us to inject out own DataTipText in the future, for example keyword help and symbolic intellisense.
Fix for Target Framework version being limited to 4.0
https://github.com/fsharp/fsharpbinding/issues/104
Merge git://github.com/fsharp/fsharpbinding
Merge pull request #119 from 7sharp9/master

Added Target Framework fix and first compiler binding commit for keyword help
Merge pull request #110 from aktowns/master

Exception thrown on tooltips in XamarinStudio(4.0)