merge with stable

aliases: provide more flexible ways to work with shell alias arguments This patch changes the functionality of shell aliases to add more powerful options for working with shell alias arguments. First: the alias name + arguments to a shell alias are set as an HG_ARGS environment variable, delimited by spaces. This matches the behavior of hooks. Second: any occurrences of "$@" (without quotes) are replaced with the arguments, separated by spaces. This happens *before* the alias gets to the shell. Third: any positive numeric variables ("$1", "$2", etc) are replaced with the appropriate argument, indexed from 1. "$0" is replaced with the name of the alias. Any "extra" numeric variables are replaced with an empty string. This happens *before* the alias gets to the shell. These changes allow for more flexible shell aliases: [alias] echo = !echo $@ count = !hg log -r "$@" --template='.' | wc -c | sed -e 's/ //g' qqueuemv = !mv "`hg root`/.hg/patches-$1" "`hg root`/.hg/patches-$2" In action: $ hg echo foo foo $ hg count 'branch(default)' 901 $ hg count 'branch(stable) and keyword(fixes)' 102 $ hg qqueuemv myfeature somefeature