Added CocktailSort and GnomeSort plus tests
Merge pull request #34 from mfrancis95/ross

Added CocktailSort and GnomeSort plus tests
DoubleQueueStack Complete
DoubleQueueStackTest Complete
DoubleQueueStackTest Complete
LinkedDeque
LinkedDeque and Test Complete
Merge pull request #35 from mfrancis95/ross

DoubleQueueStack and LinkedDeque
Merge pull request #36 from mfrancis95/mike

iterate() and ArraySet
Optimised the insert(), prepend(), and remove() methods.
Added cardinality() method.
Merge origin/master into mike
Minor edits to make it less confusing.