Merge pull request #3 from TACOMA-team/master

some fixes
Small change to the test_BeliefFromSensors.c to make it work independtly of the order in which files are read.
Updated the licence, the doc, the version, the version log
Removing the Sets_union function as it already exists as Sets_disjunction
Just updated the copyright dates in the doc pages. Added a contributors page.
Added a function to get the complete set to Sets. Replaced the comparison using Sets_equals(complete/emptySet) by a simple test on the cardinality of elements, way faster and way simpler.
completed tests in belief from sensors.

The file used different model for testing. It now used only the unitttest
model as it was intended to.
added a travis.yml file to compile on travis-ci.org.