calendar plugin: Autocreate archive pages if needed
Simplifying code

Thanks to review from http://ikiwiki.info/todo/calendar_autocreate/
Clarifying documentation

Thanks to review http://ikiwiki.info/todo/calendar_autocreate/
link
Adding back template information that should not have been removed

sorry...
Added option `calendar_fill_gaps`
Making use of the transient plugin
Update documentation regarding automatic rebuild whenever `calendar_fill_gaps` changes
Calendar pages are now rebuilt when previous or next page have changed
Indentation
typo
Deleted unnecessary code
Corrected error: month pages were created even without calendar_autocreate config option
Merge remote-tracking branch 'spalax/calendar-autocreate'
fix some typos
calendar: add calendar_autocreate option, with which "ikiwiki --refresh" can mostly supersede the ikiwiki-calendar command. Thanks, Louis Paternault
Fix broken links in the basewiki
Work around Debian #771047: use a non-blank SVG for the regression test

Inkscape loses the bounding box of a SVG with no content when it
converts it to EPS, and ImageMagick does not have a special case for
converting SVG to PNG with Inkscape in one step (which Inkscape can do);
it prefers to convert SVG to EPS with Inkscape, then EPS to whatever.
Fix numeric comparisons with undef
Merge remote-tracking branch 'origin/master'