SparkMD5 file reader test, incremental and normal md5

Please note that the advantage of doing an incremental md5 is to keep memory usage low.

Keep an eye on the memory usage of your browser. If you got chrome, open about:memory to see all the browsers memory usage (you must refresh continuously).
With normal md5, you should observe slightly faster times but high memory usage (because the entire file need to be read into a binary string).
With incremental md5, you should observe stable memory usage but slightly higher times.
Be aware that while using normal md5, the browser can crash due to high memory usage.