Add SelectorFormat linter

Change-Id: I9786e9a8cc95d9b0931d350ed393112bc69bbe6b
Reviewed-on: http://gerrit.causes.com/43023
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>
Add BEM convention to SelectorFormat

This seems to a be a popular naming convention, so include it in the set
of presets.

Change-Id: I5c1d3157cf503f2721a34e4ebff6ada2bb3055a8
Reviewed-on: http://gerrit.causes.com/43024
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>