- webui now calls a hook to indicate a session end
- loader.py now set a lodel.dyncode module exposing dynmically generated code

- calling check_data_value on filters value to ensure value casting

In post reccursion processing on select

	The UniqID datahandler has to call the datasource
	LeObject has to be able to determine wich parent class define its UID datahandler
	[NOT IMPLEMENTED] the datasource should be able to select with an abstract LeObject as target ( see #92 )

- bugfixes in connection string generator
- bugfixes in garbage collection of opened connections

- The LeUpdateQuery implementation is broken or at least have huge performance issue
- Moved LeObject exceptions and LeQuery exceptions in lodel.leapi.exceptions

- now datasources are declared with two conf keys : read_only and identifier
- the old datasources plugin hook is now declared in lodel/plugin/core_hooks.py. This file is imported after lodel/plugin/hooks.py in the loader.py

- Enables connections saving & auto cleaning
- Preparing possibility to declare a datasource as read only

- Now delete & update methods use filters & rel_filters

- Implementation of the delete, insert and insert_multi methods + first implementation of the select method in the MongoDB datasource
- Added parsing methods in the mongodb/utils module

- The check method checks, for now, if all the needed parameters are passed to the connection string
- A test class has been written with some bad connection args examples