Revert "Issue #929: Partial fix (don't handle 'super' invocation) using a let so that no"
and "Issue #929: Fix tests broken by additional let when making sequences"

This reverts commit 431e3099e4a23dbba1952fd50a0d94172d74909f
and commit 020d2143ce7972575bcb79a8dc0f7ed103a7fdb5.

This 'fix' causes other problems, and I think we should fix the invocation
builder to be able to generate 'safe invocations' as described in #929
which should fix 'super' instantiations too
ant tasks: Major rewrite of the ant tasks, in support of simplifying the SDK build.

* Bring some consistency to the nameing of the classes, based on the name of
  the underlying ceylon tool subcommand they execute.
* Support the use of <moduleset> and <reposet> which can be declared at the
  top level and referred to in a task via a 'refid'
* Use an 'antlib.xml' descriptor so that tasks are now declared using

    <typedef
        resource="com/redhat/ceylon/ant/antlib.xml"
        classpathref="ant-tasks"/>

  Rather than the old <taskdef>. This has the effect that <ceylonc> is now
  known as <ceylom-compile> etc.
* Print deprecation warnings when old-style usage is detected.
* Use a common base class (CeylonAntTask) for tasks which wrap invocations
  of ceylon tools.
* Get rid of ModuleAndVersion, and just use Module (which may have a verion
  optionally). This represents a small loss of type safety (but who care because
  this stuff isn't supposed to be a Java API which people actually use), but
  means we can have a sane Module.equals() which works properly for the
  ModuleSet
ant tasks: Fix the tests
Delete old tests of the ceylonc, ceylond and (old) ceylon **scripts**, which no longer exist
Mark test for #929 as failing
Fixes for the way ceylon-sdk is now laid out