add optional key-word argument to compact tickets display

[Steffen Hoffmann]

If there are lots of tickets/day (consider the - now configurable - due_date mode and 10+ tickets i.e. grouped for a major release milestone at end of month), someone may want to opt for just a comma separated list of ticket numbers instead of one ticket per line with summary.

Discuss, if you imagine this being another option worth implementing. If so, how would you name (short) the keyword for it, and would you want to see the summary (not the description, right?) in the tool-tips then? Other suggestions are welcome too.

[Steffen Hoffmann]

After encountering calender views with enormous rows expanded by long ticket lists I decided, that it would be mandatory to be able to condense these ticket lists, especially in use cases heavily depending on synchronized ticket due dates.

So changeset [8308] introduced a new optional and configurable threshold. If total number of matching tickets is equal or greater than that value, ticket summary will be suppressed and tickets are shown in minimal form: as comma-separated list of numbers. For this conditional switch each day is evaluated independently to preserve old ticket list style for days with few tickets.

[Steffen Hoffmann]

(In [8315]) WikiTicketCalendarMacro: Finish release of trunk features to maintained branches, closes #7172 #7390 #7410.

Release new ticket 'list_condense' function to 0.12 branch and backport it to 0.11 branch as well. Fix unreported bad inline CSS creation introduced with changeset [8263] for version 0.8.4 of 0.11 branch (0.8.5 was affected as well).