Updates to Uint128 and Bytes

[beauhoyt]

• Update Makefile moving go tool cover -func=c.out to the make test statement
• Update README.md adding badge for build/test with github workflows
• Add refactor Parse() breaking out logic into getNumAndUnitRunes() and getMultiplierForUnitString() to reduce high gocyclo complexity
• Added support for processing negative numbers to getNumAndUnitRUnes() so that we can throw proper errors when we get bad negative values.
• Change Type() to return bytesize.Bytes instead of bytes
• Update String() to return default value Lo uint64 as B Bytes. Though it should be impossible to hit this, but we have it just incase.
• Fix unit test for TestParseErrors()
• Add TestSet() and TestSetError() for testing Set()
• Add TestGet() for testing Get()
• Add TestType() for testing Type()
• Add TestUnmarshalText() for testing UnmarshalTexT()
• Add methods to Uint128: AddErr(), Add64Err(), SubErr(), Sub64Err(), MulErr(). And Updated Mul64Error() to Mul64Err().
• Add method to Uint128 FromBigErr()
• Update unit test for Uint128 to support new Err Methods: TestUint128()
• Add unit test for Uint128 to support new Err Methods: TestArithmeticErrors(), TestOverflowAndUnderflowErrors(), TestTrailingZeros(), TestOnesCount(), TestRotateLeft(), TestRotateRight(), TestReverse(), TestReverseBytes(), TestLen()