Added filter-in and out description

A little definition of what are doing the 3rd and 4th element of the
patterns array
Merge pull request #485 from dvdvck/patch-1

Added filter-in and out description
fix(log): use grunt.log.wordlist
Merge pull request #488 from stephanebachelier/log_wordlist

fix(log): use grunt.log.wordlist
2.6.1
Close #491 PR: Srcset regex should match any valid image candidate string.
2.6.2
changed custom pattern behavior to merge isntead of overwrite
Merge pull request #492 from timhettler/merge-custom-patterns

Changed custom pattern behavior to merge instead of overwrite
Bump devDependencies.
Merge github.com:yeoman/grunt-usemin

* github.com:yeoman/grunt-usemin:
  Bump devDependencies.
  changed custom pattern behavior to merge isntead of overwrite
  2.6.2
  Close #491 PR: Srcset regex should match any valid image candidate string.
  2.6.1
  fix(log): use grunt.log.wordlist
  Added filter-in and out description