Removed ^ power operator as the precedence cannot be set as its already been defined by Swift
Set ~ operator precedence
Changed the sqrt method to use the overflow division operator
Given the power operators ** and **= the correct precedence according to the standard order of operations (BODMAS)
Added test to cover precedence of unary minus over power operator
Added test for double negation
Added overflow operators
Allowed the lenient handler to ignore losses in precision
Added tests for overflow operation &