add : Python-specific tips and examples to various sections

[LGD-P]

In Python Loops section :

• over dictionary with .items()

In Classes & Inheritance section add :

• use case of @staticmethod

Add section : Date & Time Handling

• Current date and time
• Creating specific date/time objects
• Converting between date formats
• Timestamps and Unix time
• Date difference and timedelta

In Miscellaneous section add:

• example of the Dispatcher Pattern