Update Markdown files

- Fix hard wrapping and indentation.

license.markdown:

- Add a proper Unicode copyright symbol.

- Update year.

readme.markdown:

- Add a mention about OS X support.

- Update code sample.

- Update prerequisites.

- Fix Travis link.
Update ignore lists

- Remove *.fuse_hidden* from .gitignore.

- Have Sublime Text ignore everything that .gitignore does.
Move from lowerCamelCase to snake_case
Use smart pointers in the window class