Design shRNA guide sequences and, optionally, their cloning oligos.

Scores every possible guide window in an mRNA using position-specific
efficacy data from Matveeva et al. (2012), then — with --backbone or a
manual --loop/--adapter-5/--adapter-3 — designs ready-to-order cloning
oligos for the resulting candidates.

Three ways to run it:

knockknock                          interactive TUI: file picker, then explorer

knockknock targets.fasta [OPTIONS]  score from the command line (the word "run" is optional)

cat targets.fasta | knockknock -    pipe a sequence or FASTA in on stdin

--guide/--batch design oligos directly from a guide you already have,
without scoring a FASTA at all. Full reference: docs/CLI_MANUAL.md.
