Add simple expect functionality.
The expect(string) function will wait for input from the tty device and
only return when there is a string match. Regular expressions are
supported.
Example:
script = expect('password:'); send('my_password\n')
On some platforms calling high()/low() to switch line states result in
costly system calls whick makes it impossible to swith two or more tty
lines simultaneously.
To help solve this timing issue we introduce a tty line state
configuration API which can be used instead of using
high()/low().
Using config_low(line) and config_high(line) one can set up a new line
state configuration for multiple lines and then use config_apply() to
finally apply the configuration. This will result in only one system
call to instruct the serial port drive to switch all the configured line
states which should help ensure that the lines are switched
simultaneously.
Example:
script = config_high(DTR); config_low(RTS); config_apply()
Add support for running Lua scripts that can manipulate the tty control
lines. Script is activated automatically on connect or manually via in
session key command.
The Lua scripting feature opens up for many posibilities in the future
such as adding expect like functionality to easily and programatically
interact with the connected device.
