Update deprecated methods

There are a few deprecated methods that I decided to keep for various reasons: 
1) minimumFontSize is kept to support older phones
2) Dismissing or presenting view controllers is deprecated, but keeping it for 
support of older apps.
3) Largest change is viewDidUnload. viewDidUnload is only called when the
controller's view is released from memory. Usually called when a low-memory
condition occurs and this view is not needed. 

In iOS6, viewDidUnload is NEVER  called because views are no longer purged under low-memory conditions. Instead  Apple want's developers to use didReceiveMemoryWarning. To make the app compatible with older iOS versions, I kept the viewDidUnload method and moved the variables that should be set to nil to the didReceiveMemoryWarning to make iOS 6 happy.