Track image file

This file is crypted as all the bpk files in Death Rally.

Once decrypted its contains the palette and the image (background) of the circuit.

Offset (byte)	Size (bytes)	Information
0	10	RIX3-header
10	768	circuit palette (for reversed circuit, the game use TRX_FLIP.PAL)
778	circuitHeight*circuitWidth	The image of the circuit.

CircuitHeight and circuitWidth are defined in TRX_INF.BIN file