[web] Return useful error messages when exceptions arise in ajax controllers (closes #3932503) The call to super() in RemoteCallException passes 'reason' all the way to python's Exception.__init__() which is then stored in Exception.args. This way, CubicWebPublisher.ajax_error_handler() gets a useful error message when calling unicode(exc). The change to uilib is just to prepend the exception type name. Just a small improvement.

[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