Implemented EZP-15040: Support for more than 30 languages
Added test for case insensitive field criterion
Make field matches in PostGreSQL case-in-sensitive

Potential issues with this solution:

1) This might be a performance drawback, since all column values must be
   converted to lowercase on each query.

2) PHP and the respective database might have different ideas on how to
   lowercase certain non-ASCII characters. This could lead to issues with
   certain multi-byte encodings in some languages.
Do not lowercase database values

The values are, at least with the current fixtures, already lowercased.
Once indexing is implemented in the legacy backend the lowercasing
should happen there. The old legacy implementation seems to already
implement the lowercasing:
https://github.com/ezsystems/ezpublish-legacy/blob/master/kernel/classes/datatypes/ezstring/ezstringtype.php#L374
on index creation.
Implemented: transformByGroup()

This feature is used to, for example, lowercase random strings in the
ezpublish-legacy, and we need this right now, too.
Use transformation processor to lowercase strings

The same method is used in the legacy implementation to lowercase the
database values. Thus this should be safe and work around issues with
libc implementation of strtolower().
Fixed criterion handler construction in test
Added required PHP extensions in composer.json
Added more required PHP extensions in composer.json
Merge pull request #493 from patrickallaert/EZP-15040

Implemented EZP-15040: Support for more than 30 languages
Merge pull request #352 from ezsystems/phpextensions_composer

Added required PHP extensions in composer.json
Removed $query parameter from findSingle() again

Since findSingle is used to locate exactly one item, the $query parametr
with applied scoring and fulltext matching does not make sense here.

Removing this parameter here, also means we will not break the API in
this regard.
Added: Additional properties to fulltext search criterion
Added: First unit test for Solr fulltext criterion visitor
Merge pull request #495 from ezsystems/field-case-insensitivity-raw

Fix EZP-20851: Uniform search casing for better pgsql support
Extracted field mapping into its own class
Implemented: Visiting of fuzzyness and boost on fulltext criterion
Tested: Boosting unknown field
Implemented: Integration tests for advanced full text search query
Merge branch 'master' into search-filter-refactoring