Add makeDir() for all parent paths on suggestOnConflict

For the saveFileset() method to check all the parent
paths, they must be created. makeDir() is now called
for each CheckedPath instance once all version suffixes
have been added.

This doesn't attempt to cleanup the created parent paths
if the import fails.
Fix NPE if no container specified.

This can happen if no screen specified while importing a plate.
merge develop --exclude conflict needs-fixes broken: PR 556 (FS-lite file security)
merge develop --exclude conflict needs-fixes broken: PR 577 (9821 Major FS refactoring)
merge develop --exclude conflict needs-fixes broken

Repository: openmicroscopy/openmicroscopy
Already up-to-date.
Merged PRs:
  # PR 556 joshmoore 'FS-lite file security'
  # PR 577 joshmoore '9821 Major FS refactoring'

Repository: openmicroscopy/bioformats
Updating 96c615b..bf12f46
Merged PRs:
  # PR 305 rleigh-dundee 'LIFReader: Add User-Comment tags to the series metadata'
  # PR 317 melissalinkert 'Add support for Inveon data'
  # PR 319 melissalinkert 'Add support for JPEG-2000 compression with code 34712'
  # PR 320 melissalinkert 'ImageJ plugin option improvements'
  # PR 325 sbesson 'Return Bio-Formats version in bfCheckJavaPath() (rebased onto develop)'
  # PR 326 joshmoore 'Sprint 4 bug fixes (rebased onto develop)'

Repository: ome/scripts
Updating 457e85a..272c83a

Repository: openmicroscopy/ome-documentation
Updating 2e32665..bc8e28f

Generated by OMERO-merge-develop#107 (http://hudson.openmicroscopy.org.uk/job/OMERO-merge-develop/107/)