Multipart: add custom parts
Fix crashes caused by miscast of JsonObject to JsonArray or vice versa.
Add asset stream support. Refactor stream loaders.

TODO: asset stream tests.
move stuff into assets.
Asset loading: fix path creation. Add unit tests.
fix bitmap exit test link
add post process for bitmaps
gradle...
gradle...
gradle...
Change behavior on placeholder and error drawables to not stretch automatically.
fixes up drawing placeholder/error drawable
IonDrawable fixes:

Fix recycling bug. #271
Refactor how error and placeholder resources are loaded.
Support animated placeholder/error resources.
Ion imageview and bitmap loading enhancements:

Add getBitmap and getBitmapInfo calls.
Refactor bitmap and imageview code into two classes.
add support for multiple post processors.
Switch back back to drawing the placeholder into the entire bounds. Placeholders should be 9 patches.
intrinsic width/height are now whatever is the primary drawable at the time. do not force resize width/height.
Switch the default verifier to BrowserCompatHostnameVerifier.

Fixes wildcard subdomain issues. The strict verifier is a bit insane.
Support resizing of just width or height.
Fix imageview load regression (excessive unregister).
Add support for hinting image dimensions from ImageView LayoutParams.
Fix recycling bug. Any time the callback key changes, must cancel.
Call unregister in cancel. This may be bad?
Execute or defer the bitmap action after the imageview unregisters.