Adding cursor pos function framework
Working on *MousePosition functions
Window Show/Hide API
Removing Event class. Changed Window::PollEvents
glfwPollEvents() polls all events for all windows. No need to call it for each window, so it's now a static method. If a user wants to stop windows from polling any events there will be an API for freezing/unfreezing event handling.

Event class was removed, it's irrelevant. Bakge internally handles window and input events, users just have to respond to and configure the EventHandler interface funcs.
Merge pull request #37 from palistov/palistov_window

Merge recent window changes