Show error/warning changes for static analyzers

Also add more caching for generated stats pages.
Use tag name for build links if there is one
arx: Prefer unity builds with MSVC

With MSVC release unity builds are *much* fatser than debug non-unity
builds!
Also build the latest tag (besides branches)
Print local index URL for each branch being built
toolchains/run.cpp: Add support for using a PTY
Run multiple builds in parallel
arx: Start slow clang-analyze process first
innoextract: Start slow clang-analyze process first
Keep tags updated