[zendframework/zf2#1713] Minor CS/flow fixes
[zendframework/zf2#1713] Minor CS/flow fixes

- use sprintf() for exception messages
- use get_class($this) instead of get_called_class() when in non-static
  context
- make conditionals positive when possible for readability
- remove Zend\I18n\Filter\FilterPluginManager and put configuration in
  Zend\Filter\FilterPluginManager

Maks3w/zend-i18n,zendframework/zend-i18n,mlocati/zendframework2-i18n-v3,MadCat34/zend-i18n