Basic implementation of localized string messages

The message strings can now be customized via locale files and can be accessed thru the new FinanCalc\Utils\Strings class

Streamlined the initialization procedure

If you're not using Composer, you need to include the "init.php" file in the stead of "src/FinanCalc.php"

PHP 5.4 compatibility

Reworked tiny bit of PHP 5.5 code which caused the whole project to be reliant on PHP version 5.5 and greater

New SimpleDiscountCalculator

Added calculator for calculating simple discount

New SimpleInterestCalculator

Added calculator for calculating simple interest

New getters for AnnuityCalculator and DebtAmortizator

Annuity and debt end date getters
Annuity length getters

TimeSpan utilized in AnnuityCalculator and DebtAmortizator

The AnnuityCalculator and DebtAmortizator classes are now using TimeSpan class for defining a period length

New TimeSpan

Added TimeSpan class which can used to define time intervals

Improved factories

The MANUFACTURED_CLASS_NAME field in factories is now leveraged to create new instances via reflection

New StockDividendDiscountModelCalculator

Added dividend discount model calculator for determining a stock's price (fair value)