Added quest persistence

Tests if quest is already apart of the table otherwise it adds itself to
the table.
Quest progress is now saved on Quest Accept and Turn in as well as on a
global step timer.
Added saveQuestProgress function and minor fix

saveQuestProgress serializes the tables quests and currentObjectives to
store into files.
Also, I freed up some memory by setting sourceData table to nil after
all initial looping since it isn't needed any further.
Added quests file creation
Moved saveInitialStuff code to encdoe.lua instead
Added saveInitialStuff's code here
Added quest and currentObject deserialization