Add Linux FTDI driver detection

[PropGit]

Add support for Linux FTDI driver detection.

This should be used for logging as well as an error check before downloading to prompt the user that there's a specific roadblock in their way. Ideally, it will provide instruction and a link/button to get the necessary drivers installed.

This relates partially to Issue #35.

[zfi]

Version 0.5.1 has detection code for Ubuntu Linux distributions. Need testing on other distributions.

[PropGit]

@zfi - How do you want to handle testing on other distributions? I only have an Ubuntu test system. Can we have @dcarrier-parallax test?

[dlcarrier]

Here's the log from Ubuntu Linux:

2017-03-09 10:40:09,190 - blockly - INFO - Logger has been started.
2017-03-09 10:40:09,190 - blockly.main - INFO - Creating logger.
2017-03-09 10:40:09,196 - blockly - DEBUG - FTDI module load state
2017-03-09 10:40:09,196 - blockly - DEBUG - ftdi_sio 53248 0 - Live 0x0000000000000000
usbserial 53248 1 ftdi_sio, Live 0x0000000000000000

2017-03-09 10:40:09,206 - blockly - DEBUG - kern  :info  : [  +0.004168] usbcore: registered new interface driver ftdi_sio
kern  :info  : [  +0.000069] ftdi_sio 5-1:1.0: FTDI USB Serial Device converter detected

2017-03-09 10:40:09,436 - blockly.main - INFO - Logging is enabled
2017-03-09 10:40:09,436 - blockly.main - INFO - Application launched from 
2017-03-09 10:40:09,437 - blockly.main - INFO - Operating system is posix
2017-03-09 10:40:09,437 - blockly.main - INFO - Initializing the UI
2017-03-09 10:40:09,519 - blockly.main - INFO - Client IP is: 10.10.20.133
2017-03-09 10:40:09,519 - blockly.main - INFO - Port number is: 6009
2017-03-09 10:40:09,519 - blockly.main - INFO - Disk log file location is: /home/davidc/tmp/BlocklyPropClient.log
2017-03-09 10:40:09,523 - blockly.main - INFO - Initializing the UI menu
2017-03-09 10:40:12,895 - blockly.main - INFO - Opening Quit dialog

[PropGit]

Thanks @dcarrier-parallax - that proves that the driver detection is working!