New option --split-sequence and fix '--format nuke' minor bug.

This release adds a new option which turns out to be quite handy in certain circumstances. For example, it can be the case that when editorial has chosen two shots from the same ARRI clip, that they won't include ALL the frames from the clip, but only two sub-sequences that cover (with extensive handles perhaps) the two shots needed for the edit.

In prior version of lsseq, you might see a the sequence with a very LONG frame range, but an almost equally long list of missing frames between the two shots. Nuke has a "split seq" toggle in the read-node dialog box that lets you see the sequence as if it were two sequences; of course letting your read them both with separate read-nodes.

Now lsseq also provides this option with --split-sequences. From --help:

--split-sequence
    prints sequences with missing frames as separate sequences as if
    there are multiple sequences with the same name, but with different
    frame ranges. Note: this option only affects the printing of a sequence,
    not in how sequence times are calculated. In other words, sorting by time
    might not produce the results you would expect when splitting sequences with this option.

--no-split-sequence
    consider frames with the same name as all being part of the same sequence. [default]

Furthermore, in prior versions of lsseq, the --format nuke option didn't print correctly (to match what you see in nuke itself) in the case that a sequence had missing frames. When frames are missing from a sequence (and the "split seq" toggle is NOT set) nuke lists the sequence, as before, but with an accurate list of the available frames in parenthesis. Prior versions of lsseq did not print the additional info in parenthesis - Now it does. For example:

$ lsseq 
ccc02.[001-120].exr m:[51,119]
$ lsseq --format nuke
ccc02.%03d.exr 1-120 (1-50 52-118 120)

And to show off the new --split-sequence feature with our example above:

$ lsseq --split-sequence
ccc02.[001-050].exr
ccc02.[052-118].exr
ccc02.[120].exr
$ lsseq --format nuke --split-sequence
ccc02.%03d.exr 1-50
ccc02.%03d.exr 52-118
ccc02.120.exr