#50 Allow a pattern passed to listdir or dirs or iles to supply a 'normcase' property. If supplied, it is passed to fnmatch to affect case-sensitivity.
#50: Honor the pattern.normcase attribute in .fnmatch also, enabling walk and walkdirs and walkfiles to perform case-insensitive matches.
Expand tests to cover more of the new pattern matching behavior
Expand documentation around CaseInsensitivePattern.