attempt to fix intermittent Travis failures
re-enable parallel test execution for Travis
relocate TestMirroringModels to headless.misc
move TestMirroring to headless.lang.misc, make it Fixture-based
fix incorrect package declaration
split tests in headless.render into separate files
Merge branch 'headless' into tortoise
move TestDocking to subpackage
split tortoise.dock tests into suites
make tortoise tests stop leaking JobThreads
refactor tortoise stuff to use WorldDimensions
refactoring in headless.lang to accommodate Tortoise
Merge branch 'headless' into tortoise
make TestTermitesModel world smaller so it runs faster
redo DockingSuite to using headless.lang.Fixture
Merge branch 'tortoise' into wip-tortoise-language-tests