Fix Yoga's rounding issues
- Integer truncation of sizes calculated by sizeThatFits:, and utility functions. Introduced by Obj-C -> Obj-C++ conversion in previous PR
- Low coordinate rounding threshold, which results in flooring apparently valid values. Layout becomes very wrong with absolute coordinate values larger than 100 and having pointScaleFactor set to 3.
- Added by Alexey Zinchenko in Pull Request #63