debuginstall: stop looking for patch utility, just test it

Updated zsh completion from issue722.

Merge with crew-stable

convert: test cvs repository conversion

convert: workaround for cvsps.cache under Windows In non-cygwin environment, cvsps fails to create its cache directory and redirect its output to stderr. Just ignore the error and capture stderr as well.

convert: fix remote cvs file paths separator

convert: avoid interpreting Windows path as CVS connection strings. CVS connection strings regexp detect colons to separate protocols from path and login. Unfortunately, Windows paths contains colons and were interpreted as rsh connection strings.

convert: call popen2 in binary mode, with a command string.

hghave: detect cvs and cvsps availability "cvsps -h" was returning 1 in cygwin, probably because CVSROOT was unset, which does not prevent it to work correctly.

hghave: wrap command output matching