fix workflow consistency: check state/transition name uniqness in the wf when state/transition name is modified ; use the new msg argument of rql constraints to have a nicer error message on failure

[system]

db-driver   = sqlite
db-host     = 
adapter     = native
db-name     = tmpdb
db-encoding = UTF-8
db-user     = admin
db-password = gingkow

[admin]
login = admin
password = gingkow