renamed MobyleError module with a name more pep8 compliant
refactor Mobyle Errors

MobyleError is the base class of all error produced by Mobyle

UserError is the base class for error due to a user action
InternalError is the base class for error which is not produced by a
user acton
replace  mobyleError by mobyle according to refactoring error module
fix indentation
remove unused import
remove unused import
remove commented method then unused import
remove unused import
change MobyleError by InternalError (see error refactoring)
remove unused import + minor fix to follow pep8
replace MobyleError by InternalError according to erro refactoring
add new error ConfigError
Merge branch 'feature_command_builder' into develop
fix problem with argpos ordering in Mobyle service (task #71).