v0.4.0

improvements

• converted exception during building Suite into failing Case #14
• changed testers to throw TestanzaAssertionError

incompatible changes

• redesigned whole api
• created new interface Test replacing junit.framework.Test
• created Junit for converting Test to junit.framework.Test
• replaced BodyTester by CaseTester
• replaced TestBuilder by SuiteTester
• gathered all testers in Testers class