* Update table & valueSet lastUpdate
* Remove file on variable remove
Merge branch 'dev'

Conflicts:
	magma-datasource-mongodb/src/main/java/org/obiba/magma/datasource/mongodb/MongoDBValueTableWriter.java
	magma-datasource-mongodb/src/test/java/org/obiba/magma/datasource/mongodb/MongoDBDatasourceTest.java