Leverage github actions for tests and linting.
This includes fixing a bunch of issues highlighted by golangci
including:
* Dead code.
* Ineffectual assigns.
* Goto warnings.
* Nil return err.
* Reused literal strings.
* Test parameter order.
Also:
* Setup clog.
Fix toValueArray causing "missing runtime" errors due to use of toValue instead of self.toValue which causeed issues with passing values to Otto.Call(...).
Previously, it was a publically accessible but invalid value (valueEmpty).
* Deprecate internal use of UndefinedValue(), NullValue(), FalseValue(), TrueValue()
* Guard against Empty, Result, Reference values from escaping the package
Basically, check that start is less than length before trying
to take a slice.
Also, rename valueToArrayIndex to valueToRangeIndex to reflect
the fact that it does not always return a value that is valid
index (value could be length)
