Compiler warnings fixed

Dear Feras,

I'm just writing to tell you that I really like your EcoGallery widget and I'd like to add more functionality to it.

But first things first: as the initial step I've corrected all compiler warnings. The list is as follows:
* Changed raw `Class` usage to generic `Class<ViewGroup>`
* Changed deprecated `FILL_PARENT` layout param to the `MATCH_PARENT` replacement
* Removed unused private variables (please let me know if they were intended for future use, and I'll introduce the proper `@SuppressWarning` annotations instead)

Secondly, what I find missing in your widget, is a graphic indicator which picture is selected at a given moment and how many there are left until the end of the gallery. This indicator will be in form of empty circles (as many circles as there is pictures) and the current picture will be indicated by a fll circle Please let me know if such addition would make sense.

Thanks and Best Regards,

Marcin