Overhaul WinDatabase monitoring template.

* Change some datapoints back to GAUGE where it makes sense.
* Show cache hit ratios for regular cache and log cache.
* Add graphs for all collected datapoints.
Remove MSSQL2008-specific datasources.

Removes the following per-database datasources:
* CommitTableEntries
* TrackedTransactionsSec
* WriteTransactionsSec

We can probably live without these and it allows us to use the same
monitoring template for SQL Server 2005 and 2008.
Overhaul MSSQLServer templates.
Merge pull request #68 from zenoss/feature/ZEN-8667

Please review branch feature/ZEN-8667