Merge branch '2250_mcext_case_insense'

Merge branch '2250_mcext_case_insense'

* 2250_mcext_case_insense:
  Implement case insensitive for type keyword.
  Use shell instead of regex for simple regular expressions.
  Implement case insensitive for shell keyword.
  Implement case insensitive for regex keyword.
  Ticket #2250: implement case-insensitive patterns in mc.ext.