Feature: --no-cache takes a regexp to ignore matching lines in Dockerfile

- modifies CLI and server to accept a regexp for no-cache
- adds defaultable flags to mflag to support existing bool no-cache
- applies to matching RUN and ADD lines

Docker-DCO-1.1-Signed-off-by: Tim Ruffles <oi@truffles.me.uk> (github: timruffles)