Hob: add versions for compatibility check between Hob and templates

Hob: add versions for compatibility check between Hob and templates

If a user uses a very old version of Hob and does some work,
later on he/she upgrade to the latest version of Hob, because
Hob may change the settings (add more config option into the Adv.
Settings dialog or remove some), then the old templates are not
loadable and workable for the new Hob.

Even though the user hasn't save any template before, the Hob could
remember the settings between Hob sessions as a default template,
(Remember we have a bug to ask Hob remember between sessions?),
the new Hob will also load the default template.

By adding versions, we can easily to fix the issue. If the versions
don't match, Hob will remove the old default template first and
initiate a new build, which has very very little impact on the user.
(Just can't remember from the previous session after the user upgrades
to a new and incompatible Hob)

[Yocto #2492]

(Bitbake rev: d5dd9a7af9d35c588528f9937430d1ef5de216c6)

Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>