Introduce Configuration::suiteCanRun

Queries the configuration to see if a test suite can run. Removes the
filtering from `Configuration::getTestSuites`
Introduce Default Suites Configuration

Let's users specify which test suites should be run with a naked
`demeanor` command.
Add a console flag to run all test suites
Don't allow --all with --testsuite
Allow multiple --testsuite on command line
Document 'default-suites' configuration option
Document how to run non-default suites
Run all test suites on Travis
Merge pull request #7 from chrisguitarguy/default_suites

Default Test Suites