Fix order dependency in tests by resetting static variable before every test.
Sometimes when running tests (always from within IntelliJ IDEA) the headersShouldBeSetWhenRightHeaderIsSupplied test will fail. This is because the QueryThreadLocal state was not cleared between tests. Fix by clearing thread local in setUp.
Merge pull request #7 from tobli/868509b50d319d91863a5a8df54eb9eca64497af

Fix order dependency in tests by resetting static variable before every test