README: add build, coverage, LoC badges
README: add build, coverage, LoC badges

Signed-off-by: Gabor Igloi <7535f5501fd71876c93d896691e178fd3a11cfbb@citrix.com>

Frezzle/xen-api,Frezzle/xen-api,srowe/xen-api,Frezzle/xen-api,srowe/xen-api,euanh/xen-api,euanh/xen-api,euanh/xen-api,srowe/xen-api,euanh/xen-api,Frezzle/xen-api,srowe/xen-api,euanh/xen-api,euanh/xen-api,srowe/xen-api,Frezzle/xen-api