add negative Integers packing

- refactored Integer packing and unpacking
- added tests
refactor Unsigned Integers packing

- fixed crashes due to invalid internal bounds (0x80..<0x10) for values bigger than 0..<x80 range
- refactored to match Integer packing
add tests for Unsigned Integers unpacking
fix Double packing, add Double unpacking tests
remove unused performance template test to make tests run faster
minor refactoring of parseBytes
Merge pull request #4 from mr-v/numbers

Numbers