CH341A-V1.7

This is a modified SPI/I2C programmer CH341A (V1.7) with adjustable chip voltage levels. It correctly sets the chip voltage levels on the SPI /WP and /HOLD pins as well as on the I2C HOLD pins, A0 to A2.

This version is already much better than v1.0. The following defects have been removed:

 - The /HOLD signal is still connected to the 3.3V supply. 
 - The /WP signal is left unconnected.  

This is incorrect. These signals should be connected to the 3.3V supply via 4K7 resistors.