refactor(FormatManager): take google charts api as constructor and use it instead of global 'google' object
refactor(FormatManager): take google charts api as constructor and use it instead of global 'google' object

This change makes FormatManager testable. Tests still to be written.

nbering/angular-google-chart,angular-google-chart/angular-google-chart,areverberi/angular-google-chart,nbering/angular-google-chart,angular-google-chart/angular-google-chart,areverberi/angular-google-chart