mb2: support a default target if the user has one
mb2: mb2 build should now operate in much the same way as "mb build" but without the rsync
or need for mb clean

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
mb2: Remove %patch lines from spec before building
since rpmbuild complains even if not doing the setup phase

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
mb2: Only handle commands once all args are in and validated

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
sdk-manage: Update targets xml when doing a sync too

Signed-off-by: David Greaves <david.greaves@jollamobile.com>