[pvr] cosmetic: remove duplicate include of StringUtils.h
[pvr] remove unused parameter bAutoSkip in GetSubDirectories()
 [pvr] adds parent directory item to recordings list

This PR adds a parent directory item ".." to the recordings list if a
parent directory exists.
Merge pull request #3803 from xhaggi/pvr-recordings-subdirs

[pvr] adds parent directory item to recordings list