close #511810: bad rql generated when looking for vocabulary for a relation on an entity which doesn't exist (yet) technical details: * add a graph of linked variables in the RRQLExpression instance * modify rql rewriter to remove relations where an unexistant variable and or a variable linked to an unexistant variable is used. * activate this feature in Entity.unrelated_rql if the entity doesn't exists yet

[MESSAGES CONTROL]
disable-msg = C0301

[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name

[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$

[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception