Not specifying size in skin.dmf for a MAIN type causes an exception for BlitSecondaryWindows

[Drulikar]

Remotely similar to #1996; A repository that doesn't specify a size skin value for a MAIN type causes the OD client to crash on connect with the last console message being opendream.view: Loading shaders... (or in tools mode system.map: Starting...)

In addition to the events being null for that window, it also has a weird size and position:

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A codebase workaround (unsure if it doesn't cause other problems yet or they aren't just OD unimplemented issues - just 0x0 does not work despite preferencebrowser using 0x0):

OD with above change:

Byond without the above change:

With the modification (no noticeable change from normal)

Edit: I ended up just making the size be 1x480 (though 1x300 works too) since one of the pages would not scroll all the way in byond)