Implement getModelCass() for comparison with non-lazy declarations
model loader: skip module/pacakge descriptors on package load
model loader: fix for ceylon/ceylon-spec#774: do not attempt to load packages from other modules
Added test for ceylon/ceylon-spec#774
Merge pull request #1426 from ceylon/For_finishing_ide_567

Necessary changes to finalize ceylon-ide-eclipse#567
Updated tests for removal of Container from c.l
Fix for #1430: empty in then/else

Make sure we consider sequential erasure
Fix for #1431: type(tuple.rest)

Always cast when we cannot trust the type
Updated test .src for #1431: type(tuple.rest)

We generate a bit more casts
Test for #1431: type(tuple.rest)
Added overload test for #1425
Don't try CEYLON_HOME as the second option, because it's almost never any good (see https://github.com/ceylon/ceylon-lang.org/pull/246)