Previous implementation waits 300ms for response after
each command issued. But many commands finish earlier.
This patch improves the command execution time by frequently
checking for the response to complete (i.e. ends with
OK or ERROR), or the occurence of a timeout (default 200ms).
Timeout can be adapted per command to support long response
times of certain commands like AT+COPS=? (network search)
Execution time benchmark (20 AT commands/responses):
Previous: 6.010s (100.0%)
New code: 0.045s ( 0.7%)
Change-Id: I69b1cbc0a20d54791e5800bf27ebafc2c8606d93