Add debug flag and separate type checking and inference

[b-studios]

In sbt you can now call

debug

to trigger the debug mode
and

release

to trigger the release mode.

effekt.util.Debug contains a few debugging helpers that are disabled during release:

inline def debug(inline f: => Unit): Unit =
  inline if DEBUG then f else ()

inline def debug[T](inline f: => T)(inline otherwise: => T): T =
  inline if DEBUG then f else otherwise

inline def assert(inline assertion: Boolean): Unit =
  inline if DEBUG then Predef.assert(assertion)

inline def assert(inline assertion: Boolean, inline msg: => String): Unit =
  inline if DEBUG then Predef.assert(assertion, msg)

[b-studios]

This worries me a bit, but it might be unavoidable since the size computation changed a bit