Add VAT column

resolves #1
rename transaction reference

resolves #3
add buyer details

Resolves #2
Add UNSPSC code to schema

resolves #4
add electoral commission category

resolves #5
add unspsc codes
make some fields compulsory
Add elecotral committion category description
Add EC categories and VAT
Merge branch 'gh-pages' of github.com:OpenHorsham/finances into gh-pages