Parse the shader version number.

Bug 19331817

Change-Id: I53f24cec92052eb7367219c299222b02301f3a19
Reviewed-on: https://swiftshader-review.googlesource.com/2288
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>