List of MULTIVALUED_PROPERTIES is incorrect

[djpohly]

Searching the RFC for the word "comma" yields three (or four) properties which may accept a comma-separated list as a value:

• CATEGORIES
• RESOURCES
• FREEBUSY
• RECUR (although this usage is deprecated, see A.3 item 4)

The set in src/java/davmail/exchange/VProperty.java only includes RESOURCES and, incorrectly, LOCATION (which should have commas escaped - see #177).