[SyncEvolution] documentation update, enhanced command line

Hello! The "Getting the concepts clear" mail thread and a private email exchange with Todd identified several shortcomings in the documentation and/or implementation. This is my attempt to address those. A diff and the full modified README.rst are attached. Some of these changes will require changes in the implementation. In short, what I am trying to achieve is: * Better explain what local sync is and how it involves two sync configs. "originating config" gets introduces instead of just "sync config". * Better explain the relationship between contexts, sync configs, and source configs ("a sync config can use the source configs in the same context"). * An entire section on config properties in the terminology section. * Less focus on conflict resolution, as suggested by Graham. * Remove the hard-coded "target-config" name. It still needs to be there as fallback for existing configs or users continuing to use the current instructions. * Fix examples that became invalid when fixing the password storage/lookup mechanism for GNOME keyring in 1.4. I noticed that the username=email-address part should be handled without additional properties. * Fix WebDAV with DNS auto-discovery. Few servers support it, so this hasn't been noticed before. * Fix the implicit command line magic where it does some consistency checks when creating new configs. Not exactly sure yet how. I ran out of stream after updating the terminology section, the "command line conventions", "Synchronization beyond SyncML" and "CalDAV and CardDAV". It's possible that the other sections also contain slightly incorrect usage of the terminology or are simply out-dated. -- Best Regards, Patrick Ohly The content of this message is my personal opinion only and although I am an employee of Intel, the statements I make here in no way represent Intel's position on the issue, nor am I authorized to speak on behalf of Intel on this matter.