Double Dragon Loader
=====================
  info by Fabrizio Gennari <fabrizio.ge@tiscalinet.it>

Used by Double Dragon

Encoding:
---------

Threshold: 360 clock cycles

Data Endianess: MOST Significant bit First

 Lead-In Byte:  $80
    Sync Byte:  $40

Structure:
----------

After sync byte, the following information is given :

 00    Block number (identifies the block)
 01-02 Start Address of data (Low, High byte)
 03-04 End Address of data (Low, High byte)
 05    DATA

No checksum