2.2.0

• Implemented domains and added new gettext functions: d__, dp__, dnp__ (and the "echo" version: d__e, dp__e, dnp__e)
• Changed the way to load the gettext functions to fix #33. Instead being loaded automatically by composer, from now you have the static method Gettext\Translator::initGettextFunctions($translatorInstance) to load the functions and register the current translator:

//before:
__currentTranslator($translator);
__e('hello world');

//now:
Gettext\Translator::initGettextFunctions($translator);
__e('hello world');