Fix parsing negative amounts
Add multi commodity totals to balance report
Fix specs for new bitcoin transaction in spec data
Fix budget spec for ledger budget bug

Legder does not do well having multiple commodities recorded for
accounts that should be shown in the budget report. Thus we need to do
without multiple commodities in the budget report for now.
Remove gemfile lock from repository
Bump version number to 4.0.0

Latest commits have some major changes in the /balance API, giving
multiple commodities for all amounts. That´s why the new major version
number.
Release version 4.0.0