Added new test macro: VERIFY_THROW_MESSAGE. See issue #9.
Using the VERIFY_THROW_MESSAGE macro in the AccountTest.
Using the VERIFY_THROW_MESSAGE macro in the AccountManagerTest.
Using the VERIFY_THROW_MESSAGE macro in the CategoryManagerTest.
Using the VERIFY_THROW_MESSAGE macro in the ConfigReaderTest.
Using the VERIFY_THROW_MESSAGE macro in the PartnerManagerTest.
Using the VERIFY_THROW_MESSAGE macro in the ValueCalculatorTest.
Using the VERIFY_THROW_MESSAGE macro in the HmReaderTest.
Merging with the exceptionMessage branch. Fixes #9.