Initial conversion to namespaces
Backport Doctrine conversions from 2.0 @tfotis
Backport installer to Doctrine conversion done in 2.0
Backport changes from 2.0
Add back legacy.
Added upgrade routine for Users attributes. Read notes:

The current state of the upgrade after this patch is you must
run upgrade.php - since the development version is already marked
at 1.3.6 you should then manually run the upgrade of Users module
via Extensions module.
Changed typehint.
Merge pull request #674 from drak/users_ns

Convert Users module to namespace