added WIP variant definition schema, along with the old schema used by the previous version of chessmaker
Variant definition xml now loaded by the client, ready to be processed
The client now renders the board SVG from the variant definition, instead of relying on the server to do this
Pieces are now loaded and displayed from initial layout, although they're not currently centered within cells
Pieces now don't block clicking on cells
Updated theme to use lower-contrast colors for the board, so that pieces can be seen more clearly
Now loading a transform from piece appearance definitions, so that the coordinates of a piece represent the center of its image, as well as the center of its cell
Lightened theme, and made piece appearances use themed colors rather than fixed ones
Added appearance and move definitions for remaining orthodox chess pieces to test definition
Added hidden "raw" page to designer, to allow variant definition XML to be read/written directly