Fix bug 184.

https://bugs.linaro.org/show_bug.cgi?id=184

Remove 'interactive boot commands dropdown since it's not supported anymore.
Change the name of the 'boot options' field to 'custom boot commands'.
Fix the syntax for custom boot commands when generating job definition.

Change-Id: I2b233324f9cf7def26cfaafb2f6a9a711f77b5be
Fix bug #210 -  Omit retired devices from Devices passes health checks ..

Change-Id: Ib1bf23bf501e3c86a037fe932453204585f5bc13
PEP8 fix

Change-Id: I51d3e67e092852f18eccec2d6a56fb8afb925335