initialize Propel2 support
Started to work on Propel2 commands integration (only a few work at the moment)
Removed useless buildtime-conf file generation
Reorganised a bit the commands
Implemented the ModelBuild command
Revert "Removed useless buildtime-conf file generation"

This reverts commit bca3140e98c45e1624b6e40bdff8886d02758ff0.

Conflicts:
	Command/AbstractCommand.php
Implemented the SqlBuild command
Moved the schema-locating code outside the AbstractCommand
Cleaned a bit the AbstractCommand
Handle master/slave connections
Fixed classname configuration
Fixed the DataCollector
Implemented the GraphvizGenerate command
Checkstyle fixes
Implemented the DatabaseReverse command
Consider the connection option while aggregating the schemas
Add: support for param converters
Started to add tests (almost green!)
Do not ignore build properties and behaviors given in the configuration anymore
Restored the Build hub command