Inlcude file name after the SORRY line

that way bulk messages (like for missing subroutines) get the file
name exactly once (not 0 times as before, and not repeated for every occurrence either)
Start processing use more smartly.

This handles it through the usual longname parser, meaning we now can
pick out the name itself from any colonpairs.
Pass use/need colonpairs to module loader.

This also catches any use of :from<...> and complains for now; this is
the hook where :from<jvm> support will go.
Fixes spectests that were broken by 156de3be59136b3b75f4eb51c7ee1697667a5cfe
Add a mechanism to register :from loaders.
Refactor to make alternative loaders easier.

This relaxes what is returned to just be something hash-ish, not a
full-blown context.
Very basic :from<java> support.

The objects are decidedly lacking in sugar so far, not to mention the
marshalling of Perl 6 types will need a lot of work. But you can do:

    use java::lang::System:from<java>;
    say System.currentTimeMillis();

And it works.
Give :from<java> support for a :jar<...> also.
remove one usage of $.filename that now might not work anymore

but the usual code path seems to go through X::Comp.sorry_heading anyway
Make "once" block *really* work, FROGGS++ for extra pair of eyes!
Reduce core setting size by simplifying (classify|categorize)-list

Too bad that nextwith() doesn't work, or I don't know how to use it.
Remove derogatory comments
Prepare for Rakudo-specific tweaks to JVM interop.
Give objects from Java a JavaHOW REPR.

This will enable us to get them to behave a bit 6ier.
Objects from Java pretend to be Any and Mu.
Generalize Promise a little.

They can still be about a piece of code, but it's now also possible to
create an empty promise, which can either be kept or broken from the
outside. Needs some extra error handling/safety work, but seems to do
about the right thing.
Fix off-by-one in threadpool growth handling.
Implement Promise.sleep.

This produces a Promise that is kept after the specified time elapses.
Think of it like an asynchronous sleep, that doesn't block a thread.
Implement anyof and allof promise combinators.
Tentatively implement "samewith" for calling same method with different params

This is essentially syntactic sugar for &?ROUTINE.dispatcher()( self, @params );