[contactsd] Coalesce identical sim contacts to avoid duplication

This commit coalesces sim contacts with identical display names
to avoid adding duplicates to the local device store.
[contactsd] Fetch updated birthday contacts in batches

If too many contacts are updated in a short period, the birthday plugin
can generate a fetch request that exceeds the sqlite bound variables
limit.
[contactsd] Do not attempt to remove non-existent birthday events
Merge pull request #44 from matthewvogt/limit-query-size

[contactsd] Fetch updated birthday contacts in batches
Merge pull request #42 from chriadam/simimportcoalesce

[contactsd] Coalesce identical sim contacts to avoid duplication