Improve psh shell prompt, add ifconfig to recon

Add username@hostname $/# instead of just shell >
Also add ifconfig to recon for info on interfaces/local ip
Update shell help
Implement logging for exec

Update exec regex to allow for optional -o parameter and write results
of exec to file, similarly to recon. Restructure how timestamp is added
to file (do it on server). Generalize write function.
Minor client fix

When Ctrl-c, give space before printing final log.
Increase network buffer size to 4096

...because the python docs say to.
Reorganize repeated code, add default case in client parsing

There was repeated code for processing an action and optionally writing
to log file.
Fix timestamp bug

Now include minutes and don't include microseconds.
Increase size of shell data, pick correct command for network recon

Increase the number of digits used to store message size in socket
communications from 5 to 9 to support commands with potentially
tremendous output (lsof). Add check to see if data size exceeds this
increased limit and notify server.

Recon involves executing either the ifconfig or `ip addr' command.
Insert some logic to decide which command to use.
Add socket error messages to reported output