Geo: Allow to parse lat/lon as strings and coerce them

In order to be more failsafe parsing GeoPoints can support
lat/lon as strings and coerce them. Added support and test for this.

This is a part of the patch of 8b8cd26a59ece1f42ffb0f688c2ace1b3da6d083 from PR #5626
[TEST] Assert search response in MinDocCountTests#testMinDocCountOnTerms
Added trace logging in TransportSearchTypeAction and a delayed verification of test failures in MinDocCountTests.testMinDocCountOnTerms
[TESTS] Add more assertSearchResponse to aggregations tests.
[Test] added trace logging to refresh action to note which cluster version was used

Increase logging level for SearchWithRandomExceptionsTests.testRandomExceptions & MinDocCountTests to use the above and log cluster states on changes.
Upgrade to Lucene 4.7.2
Check for no open issues before build release
Separate persistent and global metadata serialization settings
Blob store-based gateways shouldn't serialize transient metadata

Fixes #5615