Add Travis-CI support
Add Travis-CI support

This pulls in the test data from its github repository, and checks that
"make check" is succcessful.  Currently, this doesn't check the Java
support, but is a good start.

kariminf/snowball,xjzhou/snowball,snowballstem/snowball,JDemler/snowball,cesarsouza/snowball,omron93/snowball,JDemler/snowball,kariminf/snowball,cesarsouza/snowball,assem-ch/snowball,goodotcom/snowball,xjzhou/snowball,goodotcom/snowball,goodotcom/snowball,cesarsouza/snowball,kariminf/snowball,assem-ch/snowball,omron93/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,snowballstem/snowball,JDemler/snowball,JDemler/snowball,kariminf/snowball,kariminf/snowball,cesarsouza/snowball,snowballstem/snowball,cesarsouza/snowball,snowballstem/snowball,cesarsouza/snowball,goodotcom/snowball,omron93/snowball,assem-ch/snowball,xjzhou/snowball,xjzhou/snowball,assem-ch/snowball,assem-ch/snowball,cesarsouza/snowball,xjzhou/snowball,JDemler/snowball,JDemler/snowball,snowballstem/snowball