Add unit test for fake screen import using CLI

OME-DCO-1.1-Signed-off-by: Sebastien Besson <seb.besson@gmail.com> (github: sbesson)
Expect SPW: true for fake screens

OME-DCO-1.1-Signed-off-by: Sebastien Besson <seb.besson@gmail.com> (github: sbesson)
Extend fake screen test to check a more complex SPW structure

OME-DCO-1.1-Signed-off-by: Sebastien Besson <seb.besson@gmail.com> (github: sbesson)
Add unit test for fake screens for .DS_STORE files

.DS_STORE files in each folder of the screen structure should be ignored when
listing the files.

OME-DCO-1.1-Signed-off-by: Sebastien Besson <seb.besson@gmail.com> (github: sbesson)
Fix TestImport.mkdir()

OME-DCO-1.1-Signed-off-by: Sebastien Besson <seb.besson@gmail.com> (github: sbesson)
Fix well index

OME-DCO-1.1-Signed-off-by: Sebastien Besson <seb.besson@gmail.com> (github: sbesson)
Merge pull request #2804 from sbesson/rebased/dev_5_0/cli_import_fake_pattern

CLI: additional fake import tests (rebased onto dev_5_0)