Merge pull request #239 from 7sharp9/master

Added portable support for FSharp.Core
Delete Microsoft.FSharp.target (lowercase)
renamed uppercase version
deleted uppercase version
renamed
renamed to uppercase versione
Merge pull request #243 from enricosada/fix_target

Delete Microsoft.FSharp.target (lowercase)
Merge pull request #244 from enricosada/fix_target2

Fix Microsoft.FSharp.Target (v2)