Added a dummy EmFieldType_icon
Added a test for EmType deletion with superiors

Changed beahvior : when a 'non-change' is asked (like +0 -0 or set ranke to actual rank) don't raise an Error

Implemented __hash__ and __eq__ for EmComponent (based on class name and uid) to test equality betwenn two instance. Allows to use "instance in instance_list" syntax

Behaviour changed for EmComponent and childs create method :
	- Takes care of duplicated names at creation
	- Handle all the checks in EmComponent method
Factorization of EmField.get_class_table() method
Added a @property method class_table_name to EmClass

Added docstrings comments to tests (for fancy output with -v ).
Fixed strange hidden failure that make tests stops on non failed tests with -f option. Those false failure seems to comes from with self.subTest blocs with functions calls that does assertion.

Moved the database initialisation functionnality to sqlsetup and fixed all the code to handle the sqlwrapper deletion

Added hierarchy tests

The EmField version cannot be tested yet (drop column not yet implemented for sqlite in Database.sqlalter)

Also add a new function is sqlutils to execute ddl

Now _fields and table MUST be class attribute.
Its important to note that _fields now consist in a list of (name, ftype) tuples and that ftype is a EmFieldType class and NOT an EmFieldType instance

Cleaning code for EmComponent
Optimizing tests for EmComponent and EmFieldGroup (running initDb in setUpModule and make a backup copy, the backup is restored in setUp)

- Now except for the modify_rank tests test_component didn't fails
- Added simple integer operation capabilities to EmFieldType_integer ( int cast, +=, -=, *=, /=, +, -, *, /, %, ...)

Maybe very bugy

Written some test setup and the begining of the __init__ test

Using sqlite db in test_components

EmComponent.create() now takes keywords arguments corresponding to the _fields property of the calling class

WARNING !!! Hardcoded rank = -1 at component creation and Hardcoded 0 as default value for EmClass icon

Changed id in uid and changed the dummy class for testing