today we can alert on trait changes. tomorrow we could support...

new value matches a particular substring
new value startswith a particular substring
new value endswith a particular substring
new value endswith a particular regular expression

all of these more advanced matches would be similar to how we do advanced processing on the "details" field for events-based alerting. with it we'll be able to:

* alert when the RHQ Agent "restart reason" trait substring-matches "memory", i.e. one of my agents was automatically restarted due to OOME or perm gen issues
* alert when the JBossAS Server "version" string regex-matches "cluster[0-9][0-9]", i.e. one of my jboss servers has changed partition memberships