[+]: try to fix tests for PHP 7.2

[+]: backport all PHP7 changes for old PHP versions (v2.2)

[+]: use php7 type-hints v2

Merge pull request voku#7 from voku/analysis-8mBV4Y

Apply fixes from StyleCI

[*]: update the changelog

[!]: "php": ">=7.0" v2.2

[+]: add a interface && a wrapper class for the database-connection

fix for MySQL >=5.7.5

the new GET_LOCK implementation has a limit on the identifier name

-> https://bugs.mysql.com/bug.php?id=80721

[+]: use new version of "voku/simple-mysqli"

[*]: only code-style