[PATCH] shlwapi: Fix PathUndecorate[AW] implementation.

[Jacek Caban]

Signed-off-by: Jacek Caban <jacek(a)codeweavers.com>
---

I meant to fix iswdigit usage, but found more problems with the function 
and ended up rewriting it.

  dlls/shlwapi/path.c       | 76 ++++++++++++++++-----------------------
  dlls/shlwapi/tests/path.c | 41 +++++++++++++++++++++
  2 files changed, 71 insertions(+), 46 deletions(-)