fix rotation with system version check

Added system version check to fix rotation issue on ios 8.
@ulechka: Could you put the opening curly brace on the same line like the function definition, remove the space before the arguments parenthesis pair and prefix the function name with `MR…` to keep the code conventions of the library?
Like this: `static inline BOOL MRSystemVersionGreaterThanOrEqualTo8() {`