Run DateBased tests

Author: daboross

.travis.yml

@@ -39,3 +39,6 @@ script:
 - cargo run --example pretty-colored --features colored
 - cargo run --example syslog --features syslog-4
 - cargo run --example syslog3 --features syslog-3
+- cargo run --example date-based-file-log
+  # we don't exactly have a good test suite for DateBased right now, so let's at least do this:
+- cargo run --example date-based-file-log --features meta-logging-in-format