change script to run unit tests

use the 'test' target provide by the setup.py
to test the librairies freshly build
add a sys.exit with a message if  any test fails
add mobyle2.lib dependencies 

add mobyle2.lib dependencies as pip does not install requirements recursively
add some option in test command

to run in travis-ci as on this plateform the building libray directory
does not follow the same rules as on other plateform
Merge branch 'develop' of https://github.com/mobyle2/mobyle2.exec_engine into develop
Merge branch 'fix_unit_tests' into develop

Conflicts:
	setup.py
remove print for debugging purpose and improve error message
replace assertion by raising execption

if the newly builded libraies directory is not found. test raise a
DistutilsOptionError instead of an AssertionError