Hotkeys show time in HH:MM:SS format (previously MM:SS)
Trap excessive duration clips in user interface as well as controller

Under normal use, this ensures that the user interface cannot ever
request a clip which is too long. Previously an http error response
would be generated to the audio url, causing an error in the html
audio component. This looked ugly and confusing.
player: update CSS to fix height and font size of arrow buttons
Add dummy argument to event type filter

For some reason certain combinations of event filters caused the
ajax http request to stop at readyState 2. Filter list ending in
'exported' was an example of this. This patch adds the argument
'dummy' to the end of the filter list to fix this problem. This
doesn't identify the root cause, but does solve the problem.
CSS changes - fix width of match column, left-align match and commentator heading