Added ability to copy/paste text, and to enter fullscreen/maximize/minimize the window

Added ability for users to copy and paste text within JavaScript:
macgap.clipboard.copy('texthere');
var clipboardContents = macgap.clipboard.paste();

Added ability for users to enter fullscreen using:
macgap.window.toggleFullscreen();

Added ability for users to maximize & minimize the app:
macgap.window.maximize();
macgap.window.minimize();

Added ability for users to determine if app is currently maximized:
var isMaximized = macgap.window.isMaximized();
Merge pull request #77 from Macmee/master

Added ability to copy/paste text, minimize/maximize/fullscreen the window