dlopen() and friends are included in libc on FreeBSD.
o Use './controller/block_list.sh' (with explicit "./") because '.' isn't on
  the $PATH by default on FreeBSD.
o Disable joystick block for now on FreeBSD due to lack of use case and
  inspiration to port :)
o Use a compatibility hack so we can use 'sed' with the same command line
on Linux and FreeBSD.
o Use '/usr/local/bin/flex' explicitly on FreeBSD since FreeBSD can have
  both BSD flex and GNU flex installed as 'flex', where the former has
  precendence on the normal $PATH.

Split esc (ethercat slave controller) code into seperate modules.
Add code to read SII eeprom of esc devices and use it for
device initialization.
Add per device thread for monitoring/recovery of devices.

Everything else stays in esc.c

Also add a lot of code for reading the ESCs eeprom with configuration
parameters. Also provide 'struct esc_device' for generic device creation
and handling based on the eeprom configuration.

The el1xxx, el2xxx and el3xxx now use this generic device.
Also the el3xxx module now properly supports the EL3102 device.

Add comments to command_server lib
Remove now obsolete ec_el_test
Fix controller_sample shell newlines

Mostly ethercat related in the ec directory.