Enabling the use of cookies on flash cards.

Update of pull request #493 .

Note that I did not test it, because of a missing dependency:
Error:A problem occurred configuring project ':AnkiDroid'.
> Could not resolve all dependencies for configuration ':AnkiDroid:_debugCompile'.
   > Could not find com.android.support:appcompat-v7:19.1.0.
     Searched in the following locations:
         https://jcenter.bintray.com/com/android/support/appcompat-v7/19.1.0/appcompat-v7-19.1.0.pom
         https://jcenter.bintray.com/com/android/support/appcompat-v7/19.1.0/appcompat-v7-19.1.0.jar
     Required by:
         Anki-Android:AnkiDroid:unspecified