Work around spaces being added when copying to clipboard.

Since the license text is wrapped in `<pre>` with `white-space: pre-wrap` empty lines make the #license-text bigger than it actually is.

So, get rid of the empty newline at the end of the license text files since jekyll adds trailing spaces when it parses those.
Merge pull request #152 from XhmikosR/no-spaces-when-copying-license

Work around spaces being added when copying to clipboard.
Refactor header.html's properties.
Use double quotes.
Update README.md.

* use a code block instead of individual code commands
* remove a ul since it only has one list item