add methods to identify orphan grammar symbols
use NBSP as marker of tree output
more logical setting of release ID elsewhere
eliminated unneeded semantic feature test
support PyElly error recovery
error handling by exception, fixed semantic feature test
error handling by exception
add option to disallow reversed rule arrows
add isWild() method, enforce no wildcards in optional sequence
fix typos
new error reporting and recovery
new error reporting and recovery, add consistency checks
extend unit tests for generative semantics
improve error recovery, add grammar symbol checks
initial import
git fix
for v0.5beta
for v0.5beta release