[2.0.0] Changes in registering of modules

Some changes:
- registerAutoloaders is called after registering modules for all modules
It low-cost operation, but very usefull: in multimodule application each module can autoload own classes.
- if in module class exists method 'initialize' it calles after registering
It can be used for registering own routes by each module

This two changes are steps to independent reusable modules

- forward to another module #121 (registerServices called in each module in dispatch loop)

- one backward incompatibility: di must be setted to application before registering modules