properly fix sort()
Tuple.java: fixed default type param value
Util: fixes for ceylon/ceylon-compiler#908
Updated Sequence.java with latest changes in Sequence.ceylon
make empty the singleton instance of Empty
Merge branch 'master' of https://github.com/ceylon/ceylon.language
document explanation for #540
this now passes typechecker
clean up disabled code in Range
Util: fixed bug in partial variadic spread: ceylon/ceylon-compiler#908
make it possible to compile Range
Merge branch 'master' of https://github.com/ceylon/ceylon.language
Bumped binary version to 4 ceylon/ceylon-compiler#948
minor code improvements
Merge branch 'master' of https://github.com/ceylon/ceylon.language
general-purpose meta-functions #177
add uncurry()
change some functions to accept Iterables and fix some tests #184
update some more functions, for #184
update string() and array() for #184