Added source cache
Added sstate cache
Added source mirror and corrected sstate mirror
Merge branch 'danny' of https://github.com/gumstix/meta-gumstix-extras into danny

Conflicts:
	conf/local.conf.sample
Disabled the SState Cache because it may not be reliable
Correct errors in README.
Correct minor typos in local configuration.  This file should,
in general, match the local.conf.sample from meta-gumstix.
Remove coreutils.bbappend.  This is fixed upstream.
Vim depends on gawk for nawk
Set PREFERRED_PROVIDERS in sample local.conf.

Several non-machine specific PREFERRED_PROVIDERS were set in
the machine configuration file.  These really belong in distro
settings or in local.conf if not set.  This commit sets them in
the local.conf.sample so users need to update their local.conf to match.
For new installs, the standard initialization does the right thing:
 $ TEMPLATECONF=meta-gumstix-extras/conf source ./poky/oe-init-build-env
Add pepper and duovero as suggested machines in the local.conf.

Users can either override the default value for MACHINE,
 $ MACHINE=duovero bitbake gumstix-console-image
or set the default value in their local.conf.
Added a zypper configuration for the Gumstix package repositories.
Removed packages already duplicated or superseded in the meta-oe layer.  Used the bitbake-layers tool