Command-line interface

[Hans5958]

Add a command-line interface which let people render Zenith videos using command prompt.

Not to be confused with #17.

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random user#8419:

we should add command line args to where we can just

@echo off
zenith.exe -render.xml whateverthefuckthisis.mid Videos\a.mp4
zenith.exe -transparency.xml whateverthefuckthisis.mid Videos\b.mp4
shutdown.exe

(seting xml's being pre saved settings ofc)