terminator -e doesn't work as gnome-terminal -e

This is a completely valid bug. xterm behaves the same as gnome-terminal (I expect g-t copied their behaviour from xterm), and we should do the same.
I need to poke around their parsers to see exactly how they handle things like escaped quotes, but we must have this fixed for the next release.

gnome-terminal uses g_shell_parse_argv() on the argument, which "does a semi-arbitrary weird subset of the way the shell parses a command line."

xterm attempts to execv() and failing that calls the shell using execlp.

I suggest we follow the latter; terminator -e "/bin/bash -c /usr/bin/python" would result in us telling vte to fork '/bin/sh -c "/bin/bash -c /usr/bin/python"' (or whatever the user's shell is). Far easier than making our own argument tokenizer.

I've committed a change to HEAD that uses the shell to spawn commands, so even "terminator -e 'cd $HOME && bash'" will work now (it doesn't in gnome-terminal, but does in xterm). Can you verify it makes terminator do the right thing?

This currently breaks -x, since "-x foo bar" ends up running /bin/sh -c foo bar.

We can either quote it so it runs sh -c "foo bar" and so -x foo \&\& bar will work as -e "foo && bar", or we can pass it directly to exec if there's more than one argument (so -x "foo && bar" will Just Work, but -x foo \&\& bar will run /path/to/foo "&&" "bar").

The latter seems like a reasonable compromise.

-x should work correctly now; -e is always handled by the shell, -x is used directly after a path lookup. The code is a bit neater too.