minor, sketch out echs filters, mapping events to events and support -f|--filter in echse-collect for that

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, also provide echs_filter_drain() to drain stuck events from a filter

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, change as slot back to const char* in echs-lisp.[ch]

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
chore, refactor echse's iterator body into materialise()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide wishful iterator for echse-collect

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide actual filter __filter() using an event fifo

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'tool/collect' into next

* tool/collect:
  minor, provide actual filter __filter() using an event fifo
  minor, provide wishful iterator for echse-collect
  chore, refactor echse's iterator body into materialise()
  minor, change as slot back to const char* in echs-lisp.[ch]
  minor, also provide echs_filter_drain() to drain stuck events from a filter
  minor, sketch out echs filters, mapping events to events and support -f|--filter in echse-collect for that
Merge branch 'next'

* next:
  minor, provide actual filter __filter() using an event fifo
  minor, provide wishful iterator for echse-collect
  chore, refactor echse's iterator body into materialise()
  minor, change as slot back to const char* in echs-lisp.[ch]
  minor, also provide echs_filter_drain() to drain stuck events from a filter
  minor, sketch out echs filters, mapping events to events and support -f|--filter in echse-collect for that
  fix, handle leap years in echs_instant_fixup() properly
  minor, accept unquoted symbols for collection items as well
  minor, wipe values from all collections on the active queue upon new events