[BZ 1095000] Fix test failures.
[749368] add @since Javadoc tags to our public APIs
Went through our intentional-changes files and added  agfew missing @since
tags that seemed maybe useful.  I had previously updated the server's
SLSB remote API, just added 4.12 for that.
Merge pull request #95 from lzoubek/bugs/1074632

Bug 1074632 - RFE: Manage storage node snapshots
Bug 1115146 - Purge (delete) data using smaller batches

Introduced JDBCPurgeTemplate

Update purge process for:
* availabilities
* traits
* events
* calltime data values
* alerts (and notif log and condition log)
* OOB

Batch size:
* is shared across implementation of the template
* is configurable through a sys prop
* value is unbounded
* defaults to 3000
[1119262 jon3-7] EAP6 drifts exclude pattern not working for windows case
The issue here is that the drift template defines the plugin descriptor
and in this case, the associated excludes filter: pattern="*_history/**/*".
It can only be predefined in one format, and the plugin naturally uses
linux-style forward slashes for the directory separator.

But on Windows that is the wrong separator.

The solution is to convert to the native separator slash internally at
"detection-time", regardless of the slashing used in the pattern.  This is,
I think, in-line with ant file-pattern approach we are using.

Also,
-- added new FileUtil.useNativeSlash(String path)
Bug 1074632 - RFE: Manage storage node snapshots

2nd piece of impl above BZ. This patch adds server side capability to manage
snapshots for storage cluster. This basically means that we regularly run
takeSnaphost operation with several parameters - so user can decide whether
to keep all of them, keep last or move older ones to specified location.

6 new private/readonly system settings have been introduced - those settings
can be updated only via Storage admin pages.

User can enable/disable snapshots management of storage cluster and set cron
expression to run management task regulary (additional 4 settings are
basically parameters for takeSnapshot operation introduced within previous
commit for this BZ). When Cluster Setting is saved in UI we re-schedule
takeSnapshot operations on all StorageNode resources in inventory.
takeSnapshot operation has been added to alert condition for storageNode
management failures, so user is notified when it fails.

Snapshot related code was removed from
StorageNodeManagerBean#runClusterMaintenance()