Updated the application to beta functionality

~ replaced the application icon
+ added a custom font (Exo2)
+ added some color constants
+ implemented a method for adding a bottom border to the URL input field
+ implemented a method for displaying an activity view during the request
+ implemented a method which checks if the user website is valid
+ implemented a method for adding a validation state label
+ added a subtype variable which checks if an info type has a warning as subtype
~ changed the if-statements to a switch-case
+ implemented 'didSelectRowAtIndexPath'
~ changed the selection color of the cell to the type-color