file:line error reports

This feature was requested in the project I'm working at, since we use unit++ from inside vim.

The new feature allows the failed assertions to be interpreted by the IDE, hence to capture and use failed test for lists or placing the cursor.

Unfortunately this had to use preprocessor macros. This has forced some incompatibilities with the previous release:
1) fail() has changed to assert_fail()
2) assert_true and assert_eq might wreck havoc, if they have been used as names for something else, where unit++.h is included.