Features:

Added a new Parser class (used internally, but I figured that someone might want to use it)
Added the ability to use interpolated strings
Parameters given to TranslatePipe will now be used for interpolated strings
Added a property currentLang to TranslateService
Added a new optional parameter interpolateParams to the method get from TranslateService
Better & faster code now that I understand Observables better :-)
Lots of documentation added to the readme & to the code
Added sourcemaps for the files

Bug Fixes:

onLangChange is now correctly triggered when calling the method use instead of when calling the method getTranslation

Renamed setDefault to setDefaultLang
Renamed onLanguageChange to onLangChange and moved it from the loaders to TranslateService
Moved useStaticFilesLoader from the static loader to TranslateService
Removed the unused property method from TranslateService