Refact stage script so it no longer depends on the pwd when when executed.

Adding move_stage script to automatically replace the ometa and terml _generated dirs with the staged dirs.
Adding support for custom labels.  The node is created but nothing is being done with the label yet.

Adding parens to barenumber rule for readability.

Fix errors in examples and adding exceptions example to test new custom labels.

Adding remove stage script.
Labels in grammers now generate label nodes.

The custom label is now added to the exception.

Add print statements to examples so usage is shown.
Adding tests for custom labels.  There are a couple of issues:

Unexpected results with ('x'*)^(Label) .

Found problem in trampolined tests where carrot is in wrong location.  This causes the label test to fail when the exception is checked.
Documenting custom labels
Fixing issue when custom label exception was joined with other exceptions.
ometa/vm: Introduce a grammar for compiling to VM instructions.
ometa/vm_emit: Start emitting VM instructions.
vm: Start using VM grammar and get tests running.
test: Alter VM builder tests to use relative jumps.

We're gonna do position-independent building.
vm: Fix OOB on single-element Or().
vm: Implement Repeat().

I shouldn't have been so lazy with this one.
terml/nodes: Fix __eq__().
vm: Clean up some of the the Apply() rules.

Still wrong, but less wrong and the tests actually say things now.
test: Fix a couple more offsets.
vm: Fix pushes().
vm: Fix Or() (again).
test: Test slower lookahead for now.

And we're now all green!
More stuff for generating VM bytecode.

Vomits on the example JSON parser for no reason.
Applying washort's comments