Support tail -f "follow" mode

[rossbuggins]

When tail -f for follow mode of log files is really useful. Something similar for clef.exe would be really useful

[nblumhardt]

Thanks for the note, Ross!

When using seqcli ingest we've been recommending tail -f and pipes for this - https://github.com/datalust/seqcli#tail-varlogsyslog - it would be interesting to know how far that gets towards what you need.

[HofmeisterAn]

I am using the following command, which seems to work fine:

find /logs -name "*.clef" -type f -exec tail -f {} \; | clef --out-seq='http://seq:80/'