Specifically, disable coverage for the Oracle-specific code, since we
don't test that under CI. By adding bulk, it helps hide fluctuations in
the actual amount of covered code.
Also stop ignoring ImportError by default. Those mostly fall into two
categories: Py2/Py3 code, which is covered since we run both versions
with coverage, or ZODB BWC code, most of which will go away.
Adds .travis.yml and scripts for creating the DBs for those tests.
Travis is setup to send coverage reports to coveralls.io (once the tests
pass).
Also adds a tox.ini and .coveragerc for checking coverage locally.
Run the tests with '-m relstorage.tests.alltests', which now behaves
like the existing '-m relstorage.tests.testmysql' et al.
Fixes an issue running blob tests with '-m'.
Jason Madden