Added basic text handling

Now Box accepts a string to display inside (can be multiline)
Finished filling with text

Supports different aligns, automatic line breaks and stretching the box.
Removed unnecessary key
Various improvements

Added contributors to package.json, removed console.dir from index.js,
updated tests and removed typos from README
Merge pull request #1 from wesolyromek/fill-with-text

Fill with text