Update database.php

Mongo class instantiation is deprecated.
See: http://php.net/manual/mongo.construct.php
Merge pull request #44 from semalead/patch-1

Replace use of deprecated Mongo constructor with MongoClient constructor.
Merge pull request #30 from panrafal/composer-json

Composer.json
Merge pull request #32 from panrafal/fix-count

Fix: count() checks for errors and throws them
Merge pull request #33 from panrafal/feature-update_safe

update_safe accepts $upsert and $multi options
Merge pull request #34 from panrafal/feature-staticconfig

Static configuration, handy if you don't use it in Kohana
Merge pull request #35 from panrafal/feature-override

Ability to override connection instance for testing purposes
Merge pull request #36 from panrafal/tests-phpunit

tests ported to phpUnit
Merge pull request #38 from panrafal/feature-staticmodels

Static models declaration, factory also accepts classnames
Merge pull request #39 from panrafal/feature-keepid

Trying to load a non-existent document will keep it’s ID in the object.
Updated @methods PHPDoc
Merge pull request #48 from sergeyklay/fix-phpdoc

Updated PHPDoc
Fallback to old Mongo() class if MongoClient() is not found

This is related to https://github.com/colinmollenhour/mongodb-php-odm/pull/44.
On dev machines it's easy to get the last MongoDB PHP driver but on production servers, this PHP driver is not necessary at the last version.
This small fix allows to use either MongoClient() or Mongo() as a fallback.
Merge pull request #49 from semalead/fallback-to-mongo-class

Fallback to old Mongo() class if MongoClient() is not found
Fixed remove_safe parameters.  may be empty
Merge pull request #50 from sergeyklay/fix-remove_safe

Fixed Mongo_Collection::remove_safe
Merge pull request #31 from panrafal/feature-helpers

Helper functions - some mirroring JS API, plus two helpers: get_query and connection
Added some DB helpers
Fixed execute_safe. If an error occurs $result  will contain 'code' field instead 'errno'
Revert "update_safe accepts $upset and $multi options"

This reverts commit feca19eac3ab1e0e130b48084fc66a5c8f8c9115.