Added support for suitable for event types and tag based keyword searches

Added support for suitable for event types and tag based keyword searches.

New field in the event object:

    "suitableFor" : [ "KIDS", "TEENS", "AGE_55_PLUS", "GROUPS" ],

In the searchable tokens tags are automatically created for these tokens. They can be searched by using the # prefix with the following tags:

    #suitableforage55plus
    #suitableforteens
    #suitableforkids
    #suitableforgroups

Example:

    http://localhost:8080/api/event?keywords=%23suitableforage55plus

Causes are now added as both keywords "Save the world" and as a single tag like #savetheworld.

Also, arbitrary tags in the description are now treated as tags. The hastag prefix is not removed.