Indicate in package.json that a version of Express lower than 4.0.0 must be used

Node displays an error coming from Express when GCLI is built because version 4.0.0 of Express removes middleware. This changes appears to fix it. The better long term solution would be to include middleware separately, as recommended in the error message, but this temporarily fixes the issue.
Merge branch 'patch-1' of https://github.com/rastus-vernon/gcli
Require NodeJS 0.10

0.8 was broken on TravisCI and there didn't seem to be much point in
working on getting it working, so we're removing explicit support.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
Merge remote-tracking branch 'gcli/master' into mozmaster

Conflicts:
	.travis.yml
	package.json