transformers no longer ignore UnApply.fun

Second time's the charm. I remember trying to do exactly the same somewhen
around 2.10.0-M4, but then some continuations tests were failing.
Luckily, today everything went smoothly.

Please note that this fix changes the way that SI-5465 manifests itself.
Previously it produced type errors, now it simply crashes the compiler.
Therefore I had to attach the try/catch FatalError clause to invocations
of toolbox methods, so that compiler crashes get caught and translated to
ToolBoxErrors.

Also fixes SI-7871, and that clears the way for implementing quasiquotes
with conventional macros rather than relying on a special case in typer.
refactors ToolBoxGlobal wrappers

Centralizes wrappers in a single location and makes it impossible to use
the compiler without going through that location.

Also fixes the option string tokenization bug that was there for ages.
This time I figured out that there's already an implementation of the
tokenizer in our compiler, so I just used it :)
Some refinement of -Xlint interpolation warning.

I had covered a few more cases working on this recently.
The warnings in several more cases involving polymorphism,
currying, and selects vs. idents receive more refined
handling.
Merge pull request #3000 from paulp/pr/xlint

Some refinement of -Xlint interpolation warning.
Merge pull request #2991 from xeno-by/topic/unapply-copier

transformers no longer ignore UnApply.fun