New method in the AbstractAdapter to check if an
Integer's value is within the range of the native PHP integer type
New tests for the new `isWithinIntegerRange()` method
New exception for out of type range errors
New `toInteger()` method for the Integer adapters
New tests for the new `toInteger()` method
Abstracting the common `isNegative()` method
Merge branch 'feature/to-int'