allow setting trigger delays in seconds instead of number of samplings

[stefanct]

the "delay" textfield(s) triggerDelay only allows for specifying trigger delays by the number of samples passed. it would be nice to be able to enter it in seconds too.
to distinguish between sample# and time based delay, i think it is enough to look for 's' in the end of the string (i.e. no new gui elements, only additional tooltip text). preferable the parser would also be able to handle n, µ/u, m as prefixes similar to NumberUtils.parseUnit (which btw should parse m and g case sensitive imho).