basic usage for screen

I'm not sure how to test this. I got the example to run but couldn't seem to get this to show up. The tests pass

```
rkm3/adds-screen npm test

> tldr@0.0.6 test /Users/rkm3/Development/github/tldr
> mocha



  Console output from Markdown
    ✓ surrounds the output with blank lines
    ✓ strips paragraph tags
    ✓ reads the command description from block quotes
    ✓ ignores all other Markdown syntax
    ✓ highlights replaceable {{tokens}}


  5 passing (16ms)
```


I had to install a bunch of dependencies. I don't know much about node. Is there a way to automate the installation?

```
npm install ansicolors
npm install ansistyles
npm install async
npm install commander
npm install connect
npm install err
npm install markit
npm install mkdirp
npm install mocha
npm install ms
npm install request
npm install rimraf
npm install should
npm install unhtml
```