possible fix for multi-method import bug

This patch allows you to import multi methods from several modules.
It merges the dispachtee lists. Two identical dispatchee signatures
dont clash yet, since I am unable to compare signatures.
Merge branch 'nom' of github.com:rakudo/rakudo into froggs_mergemulti
throw X::Import::OnlystarProto

Only if both sides have an onlystar proto the merge is allowed.
added test file import-multi.t

These tests cover the import and merging of multi subs and traits.
Merge branch 'nom' of github.com:rakudo/rakudo into froggs_mergemulti
Merge branch 'nom' of github.com:rakudo/rakudo into froggs_mergemulti
Update precedence of setops to match updated spec.
Merge branch 'nom' into froggs_mergemulti
Eliminate $*W mentions in traits.pm.

This was always a hack, unrequired for a while now.
Fix hash/array binding constraints.
Simplify and make multi merging a bit more robust.

Better duplicate elimination, and more reliable determination of what
is/isn't a dispatcher. Passes all the same tests.
Merge branch 'froggs_mergemulti' into nom
Remove out of date comment.
Update ChangeLog.
Make Junction.Str return...a Str!

Previously, it would form a Junction with everything Str'd. Thing is,
things that (fairly) expect to get back a Str when they call .Str will
then explode when they try to unbox it. This brings us in line with
Niecza's semantics, so at the very least it's convergence...
Specialize compilation of defor to fix bugs.

This makes defor use a call to .defined, not go via the Parrot v-table
function. There were some inconsistencies there somehow for roles and
modules; this makes sure defor will never give results inconsistent
with .defined.
Fix (my %) over-sharing.
Add missing parameterize method.

Fixes bug with providing args to an imported parameteric role.
fix for .write( Buf )

Before one got: No such method get_string for invocant of type str
proper try to get the string as utf8

If the recieved data cant be decoded to utf8 it will stay
a binary bytestream. This allows one to recv utf8-strings
and/or binary data.