Revert "Money __toString was returning wrong number"

This reverts commit f81c19eac676577e6005ed5d95ecbf56485e3572.
Tests: only whole numbers allowed
Currency property phpdoc
Money: always contain value, never empty string
Money: amount and decimals is always int, fixed formating if empty amount
Money compare methods
Money addition and subtract easily
Tests: refactored money decimals tests
Money: renamed comparator methods
Fixed missing currency conflict detection and added tests
Tests: Money::equals()
Tests: Money::isZero()
Tests: more Money decimals cases