Merge pull request #1 from ceylon/master

Merging upstream master
Added Ant wrapper, module ceylon.build.tasks.ant
Switched to Gateway architecture, to ensure only one single ClassLoader
creates objects in ceylon.build.tasks.ant.internal.sealed .
Removed *Support classes. Gateway is now invoked directly by Ceylon
classes/functions.
Moved execute() to AntProject
Made AntProject a class.
Removed package internal and moved package sealed one up.
Exception handling.
Exceptions
Changed class Gateway from Java to Ceylon. Stuff that can't be handled
in Ceylon yet is in class GatewayCaller.
Declaration of Ant.elements corrected
Documentation and class refinement.
Better tests and fixed convenience functions.
Package documentation changed.
AntProject.executeXml() added
Documentation corrected
Tests are now much less verbose
Merge pull request #47 from HenningB/ant-gateway

Ant Gateway