Caen V462 vme dual gate generator epics device support

Analog input:

Only one form of Ai is supported, reading the gate width.  VME parameters are 
the card number [0-4] and the signal [0-1].   The range of raw values is 0 to
99,999,999 in 100-nanosecond units.


Analog output:

Ao records are used for setting the gate width.  The VME parameters are as for 
the Ai.

Binary output:

These are used for running the gate; the vme parameters are as for the ai and
ao.  These records are asynchronous and do not complete until the gate period
is complete, so they can forward link to records which can assume the gate 
period is over.  

MBBIDirect:

This is used for status input.  The vme parameters are the card number; the 
signal is not used.  The bits are represented in their original positions; thus
B0-B10 are not used, B11 and B12 are the gate running status for gates 0 and 1,
B13 and 14 are the local indicators for gates 0 and 1, and B15 is the error bit.