Fix server-side translation response for API version 1

(And version 2 needs to be fixed too)
Catch "MySQL server has gone away" with MySQLi too and exit properly
Allow If-Unmodified-Since-Version to be 0
Remove quotes in error message to match test
Update shard.sql to match live schema
Settings sync, via classic sync and API [schema change]

Restricted to the 'tagColors' setting for the moment
Drop pre-3.0 sync clients, and update some version-related error messages
Change column name [schema change]
Additional collection-item tests
Support passing dateAdded/dateModified in item JSON
Remove unused 'libraryEnabled' field [schema change]
Fix for PHP 5.4 bug
Return 404 instead of 500 on invalid item key
Only use 'id' in clearing item cache if present
HTTP 304 response must not contain data
Merge pull request #10 from sualk/for-upstream

Two patches (http response, item caching)
Use old laststoragesync mode for API version 1
Return error message instead of hanging sync for huge notes
Use default libcurl SSL verification
Fix intermittent upload error due to duplicate relation ids