Changing graphic workshop in LTW

[ALiwoto]

Before not long ago, we used System.Drawing namespace for our graphic works on LTW game.
But now that we decided to make it cross-platform, we found that none of the features in System.Drawing namespace are supported in Linux platform.

So, we have to create one ourselves.

A new graphic workshop of our own.

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Start Date: 15 Apr 2021.

[ALiwoto]

also one more thing, we have to delete all assembly references to System.Drawing

[ArthuriaDX]

I'll work on this one from now on.