If the user wants to register a new account we check whether the
provider allows registration or not right after getting the
provider.json file and show an error msg on the wizard if not allowed.

Also, there is a new signal to handle the error raised by the server if
a registration attempt is made but is rejected with error 403.

- Resolves: #6594

Is valid for a provider not to provide locations for their gateways.

- Resolves: #7281

on the sumo tarball, the _version file for leap/bitmask submodule wasn't
being frozen, and hence BITMASK_VERSION was None. this was breaking the
provider tests w/o any clear error message.

- Related: #7322

Register to Soledad's sync (send and receive) events and display the
progress in the UI.

- Resolves: #7353

this is a bug in macholib, there's a missing letter in the plugins path, so
unless we fix this they cannot be loaded from the bundle.

See:
https://bitbucket.org/pydica/pyside-setup/commits/4b8be97e5a00b577fe30ce9aa7e5723ff2a66f94

Quoting from http://code.activestate.com/lists/pythonmac-sig/23278/:

"""
The problem might be this line:
@rpath/Contents/mageformats/libqtiff.dylib

The "i" from "imageformats" is missing!

This _might_ be related to the unusual case that "libqtiff" has no path
at all, or something else
is funny, and we end up with a name that will not be found at all.
Then the loader finds the plugin in the installed Qt, which causes it to
load everything
again from there.
"""

due to zmq, we are hitting the limit and getting app crashes.

- Resolves: #7319