Hands on #23

Twitter changed API.
<errors>
<error code="68">
The Twitter REST API v1 is no longer active. Please migrate to API v1.1.
https://dev.twitter.com/docs/api/1.1/overview.
</error>
</errors>
Hands on #23

Display error message from Twitter.
Hands On #24

Export to PDF
Hands On #24

Added watermark to PDF file