[PATCH] Added function to retrieve storage class in libclang.

[Argyrios Kyrtzidis]

Please also correct style in all places in clang_Cursor_getStorageClass, specifically
- Put a space before the left braces
- "const Decl * D" -> "const Decl *D"  (note no space between star and variable)
- "FunctionDecl const * FD" -> "const FunctionDecl *FD"
- "VarDecl const * VD" -> "const VarDecl *VD"

http://reviews.llvm.org/D5538