Decimal arithmatic with scale and precision.
Implemented addition with scale and precision on decimal.
Implement decimal arithmetic for the remaining ops.
Fix test failure.
Fix test failures.
Add in some more tests.
Address comments.
Move computation of precision and scale to compile time.
Truncate the decimal values instead of rejecting.
Minor fix.
Move calculation of decimal and scale to individual classes.
Rollout precision and decimal with an expression instead of imposing on every step.
Create an intermediate class for addExpression and SubtractExpresison to contain the precision and scale logic.
Merge pull request #90 from tonyhuang/decimal

Decimal addition, subtraction, multiplication, division using precision and scale correctly