remove base-64 code about angular-img-fallback

[dcohenb]

@diegoarcega You are defiantly right! this was done as a necessity when I first wrote the plugin.
but changing this now will defiantly not be backwards compatible.

what do you think, add another slim version angular.dcb-img-fallback.slim.js of the directive or redo it in a new non backwards compatible version?

[diegoarcega]

I believe the slim version is better, so we can choose which one to pick.

One option is to swap that base64 for this 1px transparent "image":
var missingDefault = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7";

Definitively we should have that mate.
Thanks for the great work there, the directive is just great :)

[dcohenb]

@diegoarcega I've released an update where the base64 is significantly minified.
It's should be a lot less noticeable now..
I'd appreciate your feedback