Remove unneeded casts to short
Add tests for creating pivot table in different sheets
Remove unused imports
Don't read each cell, just create records of type X
Do not set cache records
Remove unused initalizations
Add pivot tables to listen when read
Remove unused commit
Use wrapper class for CTPivotCache
Possible to load existing pivot tables
Merge branch 'pivottable' of https://github.com/karinsofia/poi into pivottable
Commit empty pivot cache record to ensure it's possible to load unsaved files