Fix sessions.py header
Add CLI/API for passing sudo parameter
sessions.py: Add call to createSessionWithTimeouts
Fix empty string bugs in SessionManagerImpl

Probably since the move to Ice, null strings in the
Principal object have been converted to empty strings
which have failed the various tests for setting defaults.
Record 'omero.sudo' in session file
Fix unit test test_sess.py
Add test_login.py for CLI
Improve `bin/omero sessions help`
Remove unused 'def sudo'
Improve login help incl. `-sudo`

Previously, `bin/omero sessions login -h` and
`bin/omero login -h` differed in their help
text. Now they match and the most basic uses
are (briefly) listed.
Fix flake8 warnings
OmeroCpp: Correct stringstream usage in cmdcallbacktest
OmeroCpp: Correct use of rbool
build: Use safe javac macro for test compilation
build: Insight tests use myjavac to avoid command length restrictions
build: Use external file with javadoc
flake8 fixes to core files
Merge pull request #2276 from rleigh-dundee/cpp-clang-fixes

C++: fixes for clang
Merge pull request #2288 from rleigh-dundee/insight-limits

build: Use safe javac macro for test compilation
Merge pull request #2290 from ximenesuk/flake8-fixes-core-dev

Integration tests - flake8 fixes to core files (rebased)