Issue #1047:
* Add support for declaring non-empty variadic functions and methods.
* For possibly-empty variadics, stop generating a default parameter value method the sequenced parameter.
* For possibly-empty variadics, in the overload method, call empty_.getEmpty() directly;
* Fix named argument invocations not not try to call default parameter value method when defaulting a sequenced parameter.
Issue #1047: Encapsulate the logic about whether there's a defaulted parameter value method, whether the default is explicitly empty etc.

Conflicts:
	src/com/redhat/ceylon/compiler/java/codegen/ClassTransformer.java
Issue #1047: Add a simple test for the declaration of variadic methods.
Issue #1047: Bulk update .src
Issue #1047: Fix for supporting partial spread arguments to methods with Variadic+  parameters.
Issue #1047: Fix a little problem with the use of Util.sequentialInstante() when partially spreading empty into a Variadic+: The call to sequentialInstance() must have a Sequential instance, but empty needs a typecast to be well-typed.
Issue #1047: Augment various tests involving Variadic* with Variadic+.

Conflicts:
	test/src/com/redhat/ceylon/compiler/java/test/expression/invoke/CallableWithDefaulted.src
	test/src/com/redhat/ceylon/compiler/java/test/expression/invoke/MethodInvocationWithDefaultedParameters.src
	test/src/com/redhat/ceylon/compiler/java/test/expression/invoke/SequencedParameterInvocation.src
Rename IndirectInvocationBuilder -> IndirectInvocation (like all the rest of the subclasses of Invocation). I've been meaning to do this for so long.
Minor tidyup of IndirectInvocation.
Issue #1155: Naming: Add a method encapsulating the $call$variadic() method name.
Issue #1155: Invocation:

* When transforming an indirect invocation, change whether we invoke Callable.$call() or Callable.$call$variadic() depending on whether the primary is declared to be variadic or not.

* Correctly generate the $call$typed() method of Callables for variadic method references.
Issue #1155: CallableBuilder: **Major rewrite** to accomodate the $call$variadc() methods needed for #1155.

The different kinds of transformation are explicitly representated as different classes.

Defer transformation of $call(), $call$variadic() and $call$typed() methods until CallableBuilder.build() is called.

Correctly generate the $call$typed() method of Callables for variadic method references.
tests: Add $LanguageAccess to the list of sources needed for the runtime compilation test
Issue #1155: tests
Issue #1155: ExpressionTransformer: A fix to explicitly pass empty as the final argument in indirect variadic spread argument invocations.
Issue #1155: ExpressionTransformer: Minor change to transformSpreadTupleArgument() for $call$variadic() methods.
Issue #1155: tests: Fixup .src for all these new $call$variadic() methods
Issue #1155: Fix an issue with boxing on indirect invocations.
Issue #1155: tests: Fix a .src for the member reference boxing change
Issue #1155: Use $call$variadic() in appropriate places, such as for variadic functional parameters variadic methods with deferred specification, etc.