Added connection timeouts on serial ports.
Fixed Missing data and "undefined header" errors.

The missing data error, where the first data point of a sweep would be
dropped was fixed by enabling software flow control(XON-XOFF).

The "undefined header" error was fixed by increasing the inter-write delay
from 1ms to 10ms.
Disabled debug output on RS232
Fixed compiler errors in hvsupply.iseg.cc
Fixed printout typos in rs232.cc
Merge pull request #213 from cfangmeier/iv_devel

Iseg compiler errors fixed