Query DSL: Cache range filter on date field by default

A range filter on a date field with a numeric `from`/`to` value is **not** cached by default:

    DELETE /test

    PUT /test/t/1
    {
      "date": "2014-01-01"
    }

    GET /_validate/query?explain
    {
      "query": {
        "filtered": {
          "filter": {
            "range": {
              "date": {
                "from": 0
              }
            }
          }
        }
      }
    }

Returns:

    "explanation": "ConstantScore(no_cache(date:[0 TO *]))"

This patch fixes as well not caching `from`/`to` when using `now` value not rounded.
Previously, a query like:

    GET /_validate/query?explain
    {
      "query": {
        "filtered": {
          "filter": {
            "range": {
              "date": {
                "from": "now"
                "to": "now/d+1"
              }
            }
          }
        }
      }
    }

was cached.

Also, this patch does not cache anymore `now` even if the user asked for caching it.
As it won't be cached at all by definition.

Added as well tests for all possible combinations.

Closes #7114.
Test: Allow CliTool to write out stacktraces

In order to have the possibility of debugging on the command line, the user
now can either set the es.cli.debug system property
which results in stack traces being written to to the terminal.

Closes #7222
Java client API: CreateIndexRequestBuilder.addMapping throws IllegalStateException if you add same type more than once

Previously, it would silently overwrite the previous mapping, which was trappy.

Closes #7231

Closes #7243
Core: Store index creation time in index metadata

This change stores the index creation time in the index metadata when an index is created.  The creation time cannot be changed but can be set as part of the create index request to allow for correct creation times for historical data.

Closes #7119
Geo: fixes computation of geohash neighbours

The geohash grid it 8 cells wide and 4 cells tall. GeoHashUtils.neighbor(String,int,int.int) set the limit of the number of cells in y to < 3 rather than <= 3 resulting in it either not finding all neighbours or incorrectly searching for a neighbour in a different parent cell.

Closes #7226