Changes

tsk72 Adds exploring by event category
Modifies EventSearchController and EventEJB so that they support advance
searching that takes into account the state and category of an event.
Adds an Explore button to templateHeader.xhtml to access
exploreEvents.xhtml.
Adds exploreEvents.xhtml, which displays a list of all the event
categories. The categories are clickable and lead to
advancedSearchResults.xhtml.
Adds advancedSearchResults.xhtml, which enables advanced searching of
events by category, state, and text.
Modifies template.properties and template_es_ES.properties so that they
include the string of the new Explore button at templateHeader.xhtml.