Merge pull request #11 from frnkwk/master

Avoid to use empty notebooks cache that generated when listNotebookWithCompletion failed.
remove beta label
minor tweaks to the sample app

Change-Id: Ifa5585b5b660b213d15a78b142520b552e56e9ee
Fix support for public notebooks. And enhancement to the Save to Evernote activity to prevent choosing readonly notebooks.

Change-Id: I5a2d7e8757c36858f457781fcd26630ca7fa074c
Support PDF display