title: Validate less with gulp including BEM
body: <p>so I have a fairly decent sized code base which is using less (many files). I want to convert the css to use BEM (actually a variant of BEM) and I would love to find a gulp way to lint the less files including naming conventions.</p>
  
  <p>Is there any way to do this? </p>
  
  <p>So basically I would like all the default css lint stuff and additionally define naming conventions that may not be broken.</p>
  
  <p>E.g. classes need to start with c-, u- or o-, other classes are not permitted.</p>