Add ENVSETUP_DIR and change include order a bit.

ENVSETUP_DIR is for supporting both ./envsetup.sh and
envsetup/envsetup.sh.

We now look for these files:

	- $ENVSETUP_DIR/envsetup.sh
	- envsetup.project.sh
	- envsetup.local.sh
guess_is_top less draconian and supports ENVSETUP_DIR.
Bump to version 1.4.

Mostly this is to support using envsetup as a git submodule. It's
sufficient for right now anyhow.
Fix not sourcing project.sh; bump to v1.4.1.