Add an `llvm::OStream` workalike class for use with `Logger::cout()`, with the crucial difference being special handling of `llvm::Type`s so they get printed by name rather than printing their full representation (which can be positively *huge*). This allows re-enabling some logger calls that were disabled due to extreme verbosity.

[Environment]

DFLAGS=-I%@P%/../lphobos -L-L%@P%/../lib -R%@P%/../lib