Remove deprecated Twig usage

Improved MultiCurrency bank handling, improved test coverage

Allows a Money instance to be converted to a string

Merge pull request #7 from merk/interval-rounding

Interval rounding support

Merge pull request #5 from merk/rounding-fixes

Rounding fixes

Merge pull request #4 from merk/rounding

[FEEDBACK] Basic Rounding

Merge pull request #2 from yethee/refactor_twig_extension

Refactoring Twig extension

Fixed composer.json, again