walk: simplify check for missing file

run-tests: redefine --with-hg so it takes the 'hg' script to run. - in parseargs(), check that --with-hg value is valid - add handy --local option for "--with-hg=../hg" - ensure that we always set PATH and PYTHONPATH (not just when doing a temporary install) - override any existing PYTHONPATH, so test success does not depend on whatever happens to be in the caller's environment - give tests a little more control by exporting $PYTHON to the environment; needed by test-convert and test-mergetool when they run hg with a stripped-down $PATH Also, add a big comment explaining all the corner cases to test for the next person who tries to modify this script.

run-tests: fix _checkhglib() so it's correct when using --with-hg. Since this makes the warning less likely, upgrade it to a "real" warning to stderr.

run-tests: factor out _checkhglib() to check import path of 'mercurial'. - rename _hgpath() to _gethgpath() and move it down next to _checkhglib() - change _gethgpath() so it caches its result: replaces global 'hgpkg' that anyone can use with global '_hgpath' that is only for _gethgpath() - no need to pass 'expecthg' to runchildren() or runtests() anymore Also: do not change global PYTHON when doing coverage; this seems to be unnecessary, since we create a dummy 'hg' script that handles coverage for us, and it made things brittle. (E.g. the rest of this patch makes the call to _hgpath() come later, and it was broken by enabling coverage.)

run-tests: show PID if running in parallel mode with -v. (Extremely handy when you break parallel operation and need to figure out what's going on. The assumption is that if you run with -v, you want more details.)

i18n-da: synchronized and updated slightly

commands: typo in bundle abort message This error trigger if one calls bundle with the wrong parameters and it is thus not an error scripts will want to look for (they could and should ensure that they call bundle with the correct parameters).