hgk: remove repetitious (and wrong) command syntax descriptions
hgk: pass --hidden switch to hg subprocesses when needed
hgk: remove no longer needed debug-rev-parse command
hgk: remove no longer needed debug-config command
hgk: set distinct fill and outline colour for non-public and obsolete changesets
hgk: show secret changesets differently (shape and label)
hgk: use switch instead of a less efficient if/elseif/if
hgk: display committer name when set by hg-git