Sync VS2010, VS2012 and VS2013 solution files
Merge pull request #296 from linquize/sln

Sync VS2010, VS2012 and VS2013 solution files
Unicode letters & operators

examples:
let ★ x = x + 5
let (|★) x y = x + y
let summ = ★ 5 |★ 5
comment about \So infix operators
apply & merge optimizations from : https://github.com/jack-pappas/fs-core-optimized , thanks to Jack Pappas
revert set.fs optimizations due complicated conflicts