List Item formatting options, Allow all day events

## Added options for the plugin
### listItemFormatter
Allows custom rendering of an event in the list by being able to set a callback which has access to the "li" and the event data
### allDayTimeString
String to use when the times for an event is "00:00-00:00"
## Added options for the events
### icon
When set will set the "data-icon" on the "li"
### url
When set will wrap the time and summary in an "a" tag and set the "href"

##Minor issues resolved
Allow a event with a start date time of 00:00:00 to be added for the day it's on