Maximizing windows that are snapped/half-maximized doesn't work.

[mathematicalcoffee]

When maximizing a window that has been 'snapped' to one half of the screen (i.e. a half-maximized window), nothing happens.

This is because in the code for maximize in the extension, if the window is already maximized in any dimension (vertically or horizontally) it is considered maximized already and unmaximize() is called on it.

Proposed fix: only consider a window maximized if it is fully maximized.