Extensions more trouble than worth it

[suau]

I'd like to suggest to remove the use of extensions completely and focusing more on the core functionality. Here are some reasons:

1. Loading a bitmap using the loading libraries is already easy enough.
2. ***FillViewportTransformations are suboptimal as they always create bitmaps matching the viewport size:
   • for bitmaps smaller than the viewport they will create unnecessary large bitmaps in memory.
   • for bitmaps larger than the viewport they will create bitmaps that will be blurry when zoomed in (which it mostly will be, that's the purpose of this library)
3. Additional feature requests regarding extensions (like issue Add callback to image loading? #23) are unnecessary as the loading libraries already implement it.
4. I briefly looked over the extensions code and it seems like requests never get canceled. This might crash or leak, depending on the library in use. Again, the loading libraries already have their own mechanisms for this in place (e.g. Volley or Ion, i'm not familiar with UIL/Glide/Picasso).
5. Images are always loaded uncached (?)

Although all of the above can be fixed, I think it's simply unnecessary as the loading libraries already do all that.

[eveliotc]

@suau extensions are meant to be completely optional, they are lazily created, you can opt-out by simply not using them.