Merge branch 'master' into ross
Edits to all PriorityQueues
Merge pull request #40 from mfrancis95/mike

Optimisations, HashMap, package changes, and indexOf()
Merge branch 'master' into ross
Merge pull request #41 from mfrancis95/mike

Map additions and optimisations, deleted Double classes
Changed prev to previous
Deleted contains()
Changed Entry to Node and entries to elements
Deleted Double classes
Changed Entry to Node
Edited List Unit Tests
Merge pull request #42 from mfrancis95/ross

Elevedder
Added capacityIncrement to constructors. Removed toString().
Added capacityIncrement to constructors. Optimised dequeue(). Removed toString().
Removed toString().
Added contains() and remove(E element) methods. Optimised classes. Removed toString() methods. remove(E element) in LinkedList needs to be implemented.