- Exploit the fact that at the end of the attribute evaluation, the only
entry on the stack should be a file set.
- Avoid String.split
- Use reference equality for nodes

This reverts commit c6e48b09.

Traverse the AST using either getChild() or getChildNoTransform()
edges, thus avoiding the jumps between the two version of the ASTs.

Traverse the AST nodes in a breadth first way when doing numbering.
External declarations from a file usually refer to top level types,
so a BF numbering will traverse as littel of the AST as possible,
thus avoiding the triggering of many rewrites that in turn load
other translation units.

For nodes that are not reachable from the root (CompilationUnit),
namely NTAs, we employ an ad-hoc DFS search.

Normally, the compiler uses a class file to resolve an import,
if the class file exists and is more recent than the source.
Change the compiler to always prefer the source file, independent
of the timestamp.

Some aspect methods are converted to attributes so that they
show up in the JastAdd attribute trace.

Added tracing with the JastAdd attribute tracer.

Move node out of partially constructed dot before inserting it in another
(qualified access parsing).

Exceptions thrown during statement code generation will no longer be
intercepted at the block level. This removes some extraneous error output and
makes it easier to trace the origin of uncaught exceptions.

Removed loading of default Java classes in JavaDumpTree so that it can be
used without relying on a JDK installation.

Moved Expr.assignConvertedType into new aspect:
java5/frontend/AssignConvertedType.jrag

Moved TypeDecl.isUnboxedPrimitive and EnhancedForStmt.iterableTypeAccess
into new aspect: java5/fronted/Utilities.jrag

Updated equations for targetType and assignConvertedType attributes in left
side of dot expressions to return the null type (to indicate no target type).