Add wildcard behavior for null endpoints in rangeQuery.

I believe the '*' range feature is a pretty common usecase of range
queries.  Right now, passing null to this function generates an invalid
SOLR phrase like 'field:[5 TO ]'.  Users can of course pass '*' to the
helper, but supporting null makes this common usecase easier to handle.

For example,

```php
$minValue = $request->get('min'); // returns null if min not specified
$maxValue = $request->get('max'); // returns null if max not specified
$range = $helper->rangeQuery('value', $minValue, $maxValue);
```

Adds support for hl.preserveMulti and per-field options.

Fixed examples for registerQueryType arguments.

update composer with alias and update travis to include 5.5

Fix suggester parser with duplicates

When asking for a suggestion of something like "blac blac", solr will return the blac suggestion 2 times.

Fix pivot facet response parsing

Changed existing endpoint var into option in bufferedadd plugin to support endpoint in config mode (#212)

Fix Spellcheck response parser with multiple suggestions

broken since 6c8ed118