[BZ 1070257 + BZ 911432] - Increasing the size of db column RHQ_ALERT_CONDITION_LOG and adding an explicit way to match alert condition on event source

messages from squashed commits:
* [BZ 1070257 + BZ 911432] - UI for alert definitions of type Event Detection and the ability to match on a source location regular expression.
* [BZ 1070257 + BZ 911432] - i18n
* [BZ 1070257 + BZ 911432] - There was a change in public constant in core/domain -> adding it as intentional api change
* [BZ 1070257 + BZ 911432] - rhq_alert_condition_log.value: VARCHAR2(512) -> VARCHAR2(4000); fixing the situation when one or both regular expressions are empty (getValueAsString() returns 'null' as a string if the form field is blank - http://forums.smartclient.com/showthread.php?t=21516)