Fix for undefined + update for 280 char limit

[BTMPL]

As this project looks to be no longer maintained, and I really love this tool, I've created a fork where:

• I fixed the "direct_message/send" undefined error which prevented it from working
• updated the maximum tweet length to 280 characters
• removed Google Analytics

Now, when I say "fixed the direct_message undefined" error I mean I removed the direct message support from the project. If someone is willing to invest their time into the project, feel free to open a PR that properly fixes it ;)

You can find the project at https://github.com/BTMPL/silverbird-2018