Add cpbuild to OmeroCpp/.gitignore
Remove errant cout
cmdcallbacktest: attempt to fix BSD runs
c++/units: attempt to fix symbol map errors
c++/units: also remove '::Units' from model test
c++/tests: enhance check and add to on cancel

The check previously added to assertFinished
is also needed on assertCancelled. But rather
than accepting any non-0 finished count as
being exceptional, only retry the poll if it's
0, meaning that no response was received at all.
Flake8 webadmin.views
Flake8 webadmin.forms
Flake8 webadmin.urls
Flake8 webadmin_utils
Flake8 webadmin.custom_forms
Flake8 webadmin.custom_widgets
Flake8 webadmin templatetags
Flake8 webadmin Selenium tests
Add webadmin flake8 to Travis
Add failing test for in-place import with read-only file
Permit passing "mode" to ManagedImportProcess.getUploader

The first time an in-place FileTransfer implementation
acquires the uploader, they "own" the location which will
be eventually contain the fileset. The method checkLocation
will touch that file path in order to check that it is
writeable. After the transfer, however, the FileTransfer
instance may no longer have write access, for example if
the symlinked file belongs to another user. Since opening
a file with "rw" requires write permissions even for the
`size()` operation, it's necessary to downgrade to just "r".
Remove Java8'ism
Minor fixes as per Colin's suggestions
Add catch to get line/file of error

It's unclear why we're currently getting a
ConnectionLostException. Locally (calling
to trout) I can't reproduce.