default log level is now WARNING

Signed-off-by: Luca Lianas <lianas@crs4.it>
using pybasex as BaseX client
removed old BaseXClient module
fixed pybasex installation command
fixed TravisCI recipe to install and run HTTP BaseX server
fixed requirements.txt in order to downlaod alpha version of pybasex
Merge branch 'pybasex' into develop
removed pyehr.libs module from setup.py