Remove ng-load and replace with ng-attr-onload with interpolation

[srallen]

Fixed #77:

• Removed ng-load and replaced with ng-attr-onload in the two places I found it.
• Interpolating in a handler, which throws Interpolations for HTML DOM event attributes are disallowed. Please use the ng- versions (such as ng-click instead of onclick) instead. in the console, but it doesn't stop the app from working. I tried without the interpolation and it didn't work in IE11. With it, the subject load and isLoading state update works in IE11 and Edge.
• Chrome and FF still working fine.

[rogerhutchings]

Seems legit, thanks @srallen