Make login window unclosable/kill resize event (orbital.rs, lib.rs)

Created by: InsidiousMind

Orbital: Added an exit flag to orbital.rs, along with adding an "e" if a window passes the flag to the file. in Window::new_flags (set to true for default)

sdl2: added exit flag (set to true as default)

Other pull requests which fix this issue but in different git submodules are under the same branch name (make-orbital-login-unclosable)

this also fixes the issue with the Resizable event firing even when the window is not supposed to be resizable.

PRS: https://github.com/redox-os/orbclient/pull/29 https://github.com/redox-os/orbital/pull/13 https://github.com/redox-os/orbtk/pull/42 https://github.com/redox-os/orbutils/pulls

Original Issues: https://github.com/redox-os/orbital/issues/11 https://github.com/redox-os/redox/issues/859