Some renames. EP19 1st try added.
EP19 solved with .NET DateTime
Problems 21 and 22 solved.
solving ep23, added ep24
Solved EP23.
Faster (about 8 times) function finding divisors/factors of number implemented.
on the way with Euler Problem 24
fixed tests
ep24 solved
First try for EP27
EP27 solved
ep27 merged into master
clean up