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.
Applying washort's comments
This one also needed a newline
Merge pull request #9 from ilmarga/master

Fixed #5

Fixes #5.
Merge remote-tracking branch 'miebster/master'
renovate error handling slightly. tests pass again.
Merge branch 'custom_labels'