VıewLoader, MaınController

Added a skeleton Maın Controller
Added a VıewLoader to standardıze the process of loadıng fxml docs.
Merge pull request #3 from halitanildonmez/halitbranch

VıewLoader, MaınController
Forgot to add MainController and ViewLoader
Merge branch 'master' of https://github.com/halitanildonmez/DD2641_Lab2 into halitbranch
Merge pull request #4 from halitanildonmez/halitbranch

Halitbranch