Added new functions to stats.py

Added a function to retrieve the implicit and explicit mods on items,
added a function to create a dictionary that contains the explicit and
implicit mods for each equipped item
Added a full inventory class variable
Added a dictionary that contains the items that are actually equipped
Add function extractdamagestats

Added the function extractdamagestats which currently retrieves all the
explicit and implicit mods from items and print them. In the future,
this function will update the damage increase class variable according
to the mods on gear
Added dictionary to store stats on items

Added a class variable itemstats to store the mods on the equipped
items, such as increased attack speed, elemental resistances and added
damage. More stats will be added in a later stage.