FR: int_overlaps with exclusive endpoints

[ismirsehregal]

It would be great for int_overlaps to gain a exclusive parameter (for both - start and endpoint).
Currently, via int_overlaps I can't properly test if a timestamp greater than 23:59:59 but smaller 00:00:00 of the next day belongs to a certain day.

# this includes endpoints greater than 23:59:59:
int_overlaps(interval(today(), today() + days(1)), interval(ymd_hms(paste(today(), "23:59:59.3")), today() + days(1)))

# but it also includes 00:00:00 of the next day:
int_overlaps(interval(today(), today() + days(1)), interval(today() + days(1), today() + days(2)))

# we can avoid this by removing one second from the first interval:
int_overlaps(interval(today(), today() + days(1) - seconds(1)), interval(today() + days(1), today() + days(2)))

# but this excludes endpoints greater than 23:59:59:
int_overlaps(interval(today(), today() + days(1) - seconds(1)), interval(ymd_hms(paste(today(), "23:59:59.3")), today() + days(1)))

For now I'm using format(my_timestamp, digits = 0L) / floor_date as a workaround.

Same question came up here:
#805
and here:
https://stackoverflow.com/questions/27280338/exclusive-time-intervals-in-rs-lubridate