AnalyseStructure.bas: Added code to start reading in the various item properties, this in turn starts to address the issue with item entries being different sizes.
Constants.bas: Add a number of extra constants to make working with items simpler
DataTypes.bas: Added some new datatypes to help convert byte arrays to various other datatypes
ESS.bas: Corrected the PropertiesChange structure
ESS.bas: Moved the PropertyScript structures to the correct location
ItemList.xlsx: Updated template with more items (a LOT more still need adding)
Items.data: Updated data from the items template file

Signed-off-by: Dasaan <mrloquax@googlemail.com>