Add binary protocol backwards compatibility for suggest highlights

This change requires different request processing on the binary protocol
level since it has been we provide compatibilty across minor version.
Yet, the suggest feature is still experimental but we try best effort
to make upgrades as seamless as possible.
Added `size` option to percolate api

The `size` option in the percolate api will limit the number of matches being returned:
 ```bash
 curl -XGET 'localhost:9200/my-index/my-type/_percolate' -d '{
    "size" : 10,
    "doc" : {...}
 }'
 ```
 In the above request no more than 10 matches will be returned. The `count` field will still return the total number of matches the document matched with.

 The `size` option is not applicable for the count percolate api.

 Closes #3440
added Lucene upgrade reminder
Improved filtering by _parent field

In the _parent field the type and id of the parent are stored as type#id, because of this a term filter on the _parent field with the parent id is always resolved to a terms filter with a type / id combination for each type in the mapping.

This can be improved by automatically use the most optimized filter (either term or terms) based on the number of parent types in the mapping.

Also added support to use the parent type in the term filter for the _parent field. Like this:
```json
{
   "term" : {
        "_parent" : "parent_type#1"
    }
}
```
This will then always automatically use the term filter.

Closes #3454
Return nothing instead of everything in MLT if no field is supported.

Today due the optimizations in the boolean query builder we adjust
a pure negative query with a 'match_all'. This is not the desired
behavior in the MLT API if all the fields in a document are unsupported.
If that happens today we return all documents but the one MLT is
executed on.

Closes #3453
Improved error message when the mapping document is malformed
Added tests for malformed mappings with no root object

This commit also makes the error message more consistent with
other exception messages in the DocumentMapperParser.
Added improvements for terms filter on _parent field similar to what has been for term filter.

Relates to #3454
improve effort into figuring out the shard associated with a search failure
Remove random empty string from test since it triggers a different exception