add LarchPluginException
add ValidateLarchPlugin function decorator
add traceback to shell error output
suppress larch/utils functions from tracebacks (closure, mostly)
add ValidateLarchPlugin to many plugins (not done)
use ValidateLarchPlugin decorator for more plugin functions
update xrf plugins to use ValidateLarchPlugin
add_plugin() returns bool (True for success) and has improved error messages
doc for add_plugin updated
better doc for FeffitTransform Group
moved layout of HTML header to theme layout
updated doc, adding community page