Fixed the email sending code to actually work.
Added and updated some help messages.

The new help messages are prettier:
[HELP] date                             - Display the current date
[HELP] ntp <server>                     - Get time from a server
[HELP] consider                         - Consider updating code
[HELP] imei                             - print the IMEI of the GSM chip
[HELP] iccid                            - print the ICCID of the SIM card
[HELP] imsi                             - print the IMSI of the SIM card
[HELP] gps [start|stop]                 - GPS start/stop
[HELP] version                          - Show the current version
[HELP] uptime                           - Show the program's uptime
[HELP] uptime 
                       - Show the program's uptime frequently
[HELP] cd <dir>                         - to change current directory
[HELP] ls                               - to list files in current directory
[HELP] cat <file>                       - to display the current file content
[HELP] df                               - to look the currently used space
[HELP] rm <file>                        - to delete a file
[HELP] pwd                              - to display the current directory path
[HELP] wget <url> <file>                - to download a file to a filename
[HELP] sms send <tel> <message>         - Send a message <message> to <tel>
[HELP] console net client <ip>:<port>   - Open a TCP connection and act as new console
[HELP] console net server <port>        - Accept any TCP connection and act a a console on each of them
[HELP] pin lock <code>                  - Lock SIM with a pin code
[HELP] pin unlock <code>                - Unlock SIM using a pin code
[HELP] pin change <old code> <new code> - Change the SIM pin code
[HELP] email                            - Send an email
[HELP] help                             - This help
[HELP] conf list                        - List all configuration settings
[HELP] conf <key>=<value>               - Define a configuration setting
[HELP] conf <key>                       - Get a configuration setting
[HELP] conf save                        - Save the configuration settings
[HELP] restart                          - Restart the device
[HELP] AT***                            - Send AT commads
[HELP] stats                            - Get some system stats
Added some javadoc around the BufferWrapper.
Added the ATExecution.setSsync method.
Simple HTTP time client: We might as well give a python3 sample in the javadoc.
Added the email and the PIN change command to the demo code.