Add MariaDB support

[prolic]

resolves #72

[coveralls]

Coverage decreased (-7.6%) to 84.263% when pulling 0da90d4 on mariadb into d55896f on master.

[prolic]

@codeliner @sandrokeil any help is appreciated! I cannot get mariadb to run

[prolic]

SELECT VERSION() give me 5.6.33-0ubuntu0.14.04.1 which indicates mysql instead of mariadb is running.

[prolic]

Ok this problem only exists with MariaDB 10.2.4, 10.0 and 10.3 seem to work, I continue tomorrow.

[prolic]

I just tested a few things, including adding a sleep 10 to the build, but sometimes I get mariadb up and running and sometimes I get mysql up. I don't know why.

[prolic]

Ok MariaDB setup on travis works now, I try to fix the rest of the tests tomorrow.

[codeliner]

great @prolic , sorry that I could not hep out

[coveralls]

Coverage decreased (-36.4%) to 55.474% when pulling 3359d69 on mariadb into d55896f on master.

[coveralls]

Coverage increased (+0.02%) to 91.908% when pulling 644e859 on mariadb into d55896f on master.