Add log messages around writes and cache R/W
 can turn on / off debugMode
Bump version to 0.6.4
400-responses to writes are not re-queued

Fixes #11
Bump version to 0.6.5
[bugfix] debug mode can now be set

$cachedResourceProvider.setDebugMode()
$cachedResourceProvider.setDebugMode(false) // turns it off
Bump version to 0.6.6
Add test around debug mode, use angular.bind

(instead of Function.prototype.bind)
Bump version to 0.6.7
Note about data persistence in Angular 2.0
Upcoming...
By default, don't clear pending writes from cache

...unless you ask for it with `clearPendingWrites`. See README.md for
details.

This puts us a bit further down the road toward #8, but there's
definitely a ways to go still!
Bump version to 0.6.8
Bump version of karma
WIP test for #5.