DeprecationWarning from elementwise comparison

There are a number of similar deprecation warnings from the test suite, e.g.:
```
test_format_change (enable.tests.primitives.test_image.ImageTest) ... /home/travis/.edm/envs/enable-test-3.6-pyqt-pillow/lib/python3.6/site-packages/enable/tests/primitives/test_image.py:76: DeprecationWarning: elementwise comparison failed; this will raise an error in the future.
image.data = self.data
```
and
```
test_bounds_default (enable.tests.primitives.test_image.ImageTest) ... /home/travis/.edm/envs/enable-test-3.6-pyqt5-pillow/lib/python3.6/site-packages/enable/component.py:394: DeprecationWarning: elementwise comparison failed; this will raise an error in the future.
super(Component, self).__init__(**traits)
```

e.g. this (incomplete) travis CI log:
[enable-segfault-pyside2.txt](https://github.com/enthought/enable/files/5667899/enable-segfault-pyside2.txt)