Hazen&Willams Calculator / Updates: Recent posts

I used a god class, because, you know, I was not able to do opposite. Now, I know the fundamentals of programming thanks to Mustafa :) I will revise it ASAP.

I have too many different lists, but today(04.06.2016) a hyrologist friend of mine bring me a paper, which has a standard ( I think it is TSE EN 12201-2 ) but we dont know which one, a list of dimentions of pipes(plastic). According to pressures, wall thicknesses chances. So I add Pressure comboBox to decrease error's and ease of use.