multi-currency support WIP
include encapsualte as money
dont store currency
work in progress. damn account balance spec
set default currency using Money
rename to match class
Merge branch 'master' of github.com:envato/double_entry into encapsulate_as_currency

Conflicts:
	spec/double_entry/locking_spec.rb
Remove encapsulate_as_money
add a currency finding method
api for setting default currency
config for global currency
remove broken spec
Merge branch 'master' into add_currency_support

Conflicts:
	spec/double_entry/account_spec.rb
set default currency in spec
keep the same pattern
fix transfer spec
fix english in spec description
switch back to Money.empty
dont check currencies here
add currencies to error message