Code polishing and efficiency improved

[Fortuntato]

The main 3 changes in terms of code (that should have not affected the functionality) are:

• Build.cs in the sort for the arrays. Changed method of sorting so that everything is ready in the desired way on the same line
• Zip Code for the company field is changed to a string because some countries (like UK) have the letters in the postcode. Also the postcode for the user address is already in string type, therefore it makes sense to keep the data fields consistent.
• Contact.cs the string check for the fields values is performed with a cleaner method that also takes into account null values. (Might give errors if there is not data at all for the variable)

[saigkill]

@Fortuntato : Thynk you very much for spending time into this code. I reviewed your Code and learned some new things. Great ideas :-) Also i checked out your branch and tested the app locally and all works fine. I merge your PR now.