[IMAP] Completed mail fetching v1

- implement imap_scheduler to control imap processes flow
- deduplication of same email in multiple mailbox
- mail fetching now only fetch diff
- separate account from mailboxes in couchdb
 (problem with big mailbox tree)
- change in client : paginate mail fetching
Fix DovecotTesting import
fix fixtures
built
fix merge mistakes
fix bug for mail with no attachments & rebased-built
debug 4 joseph
debug 4 joseph
debug /w joseph
Fixed CS: indentation should be 4 spaces
Fixed: coding style in the client. Cleaned up 'cake link'
Fixed: default parameters are now applied for each matched route (default route now uses default parameters)
Added: travis integration (close #2)
Changed: panel info now has named parameters instead of an object of parameters
Fixed: CS
Renamed all files to match cozy guidelines
Added: useful resources such as IMAP RFcs
Messages delete