v0.7.3

Adds ar extract: Extracts the contents of static library (.a) files.

Accepts multiple files, glob patterns (e.g. *.a) and response files (e.g. @rspfile).

# Extracts to outdir
$ dtk ar extract lib.a -o outdir

# With multiple inputs, extracts to separate directories
# Extracts to outdir/lib1, outdir/lib2
$ dtk ar extract lib1.a lib2.a -o outdir

Full Changelog: v0.7.2...v0.7.3