fix running on linux

Verified that bookmaker running on Linux generates same
.md files as when it runs on Windows.

Fixed a directory separator bug.
Catalog has slightly different output because some
tests generate volatile output -- need to fix this
in general.

Docs-Preview: https://skia.org/?cl=83940
Bug: skia:6898
Change-Id: I3c56c372d155b1b14a1fbdf616fa79f420b78150
Reviewed-on: https://skia-review.googlesource.com/83940
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Cary Clark <caryclark@google.com>
2 files changed