javac #1240: added a special flag for ceylon methods that we know implement at least one interface method

this avoids checking if a method's return type is compatible with its other interfaces, since in Ceylon
we can inherit the same interface multiple times with different type arguments. if one matches (the first
one in the inheritance depth-first search), then do not check the result for the next interfaces
Transformer #1240: remember the type we're actually compiling and pass it all the way to nonWidening calculations

otherwise mixin bridge methods could never find where to start looking for supertype refinements, since if the method
was not manually overridden in the current type, we'd use the qualifying type of the typed ref to start looking up
the hierarchy, rather than from the type we're currently adding the mixin bridge method to ATM.
ClassTransformer #1240: make sure we use the current type's satisfied type and the typed member's types

otherwise we were using the satisfied type of superinterfaces, which may differ from our satisfied type
ClassTransformer #1240: make sure we find the first satisfied interface to satisfy java's checks for multiple inheritance
Test for #1240
AbstractTransformer #1240: make sure we don't confuse non-class members with mixin methods
ClassTransformer #1240: Change to how we find the "best" satisfied interface

This is more inline with nonWideningType
ClassTransformer #1355: add proper wildcards to impl accessors
Updated test .src now that impl types have proper wildcards #1355
Updated test .src for #1240: different casts now that the current instantiation of the interface is correct
ClassTransformer: if an interface impl is turned to raw, force a cast because the whole method will be seen as raw by javac #1240
Fix for #1357: do not turn methods to raw by removing their type parameters

This would break clients and users of the type parameter in the method.
Amazingly this does not seem to break any test...
Updated test for #1240: we now prefer type parameters over objects when looking at the "best" satisfying interface
Updated test .src for #1357: removed rawification from some methods