more cleanup
- fixed some tests
- sql refactoring
more sql refactoring
finished sql unit test
forgot testing sql failover connections
sql refactoring
added some output to sqlite test
fixed mem leak
working on module preloading and module tests
finished (probably) module tests
added module preloading for smtp engine
- added module preloading to pipe engine
- changed pipe engine unit test
finished unit test (hopefully)
documentation
more documentation
Fix compiler-warnings

After enabling -Werror, fix a compiler-warning.
Integration of the check-library.

Check is a unit-test framework. Integrate it into the build and provide
a skeleton for the test-binary.

Later, tests are inserted into the skeleton.
Integrate test_core into spm unit-tests.

Furthermore fix some minor bugs.
New argument for smf_core_strsplit()

The nelemts-arguments is used to store the number of elements
in the resulting array.
Fix segfault in smf_core_expand_string()

If you want to format the domain of an email but the email does
not have a domain (which is legal), then you receive a segfault.

Furthermore fix a memory-leak when the formats-string contains an
unsupported format-option.