[MERGE] [IMP] crm: improved call / meeting buttons and behavior on lead and partner...

[MERGE] [IMP] crm: improved call / meeting buttons and behavior on lead and partner form view.
- improved behavior of schedule a meeting, for both opportunities and partner, with correct
attendees and options;
- removed wizard to schedule a cal, jumping to the list view with correct default values
is sufficient;
- scheduled calls is now accessible using a group, accessible through sales configuration;

bzr revid: tde@openerp.com-20140417145645-cpohfrfpqnskpok6