Switch to using common-universal-cmake.

This change involves three components.

First of all, common-universal-cmake has much stricter correctness and style requirements than was previously in yiqi, so the code needed to be adjusted to conform to those guidelines. Secondly, some imported modules fell afoul of the new rules too. Finally, there was the switch to common-universal-cmake itself, which necessitated removing a substantial amount of home-grown CMake code.