Added some heuristics to identify c style casting

Before:
void f() { my_int a = (my_int) * b; }
void f() { return P ? (my_int) * P : (my_int)0; }

After:
void f() { my_int a = (my_int)*b; }
void f() { return P ? (my_int)*P : (my_int)0; }

Differential Revision: http://reviews.llvm.org/D3576

llvm-svn: 207964