Patch 3.2.0/API changes

Development Tools

 * The default UI now contains versions of some popular (I may be biassed) tools for UI developers - /dump, /eventtrace, /framestack, and /reload [1]

Saved Instances

 * updated GetSavedInstanceInfo(index) -- added two bools to return: instanceIDMostSig, isRaid[1]
 * updated GetInstanceLockTimeRemaining -- Added Bool isPreviousInstance to return (part of the extend instance stuff) [1]

Functions

 * removed GetDifficutlyColor(level) -- Replaced by GetQuestDifficultyColor(level) [3]
 * new GetQuestDifficultyColor(level) -- exact replacement for GetDifficutlyColor(level) [3]

Arrays
Not sure of where these arrays live (global? FrameUI? QuestUI?), but this very subtle change broke several addons, so it's being included here
 * removed "QuestDifficultyColor" array -- Replaced by "QuestDifficultyColors" array
 * new "QuestDifficultyColors"array -- exact replacement for "QuestDifficultyColor" array

Unit Functions

 * updated or removed UnitIsPlusMob(unitID) -- (not 100% sure, but believed to have been removed)

Quest Maps
There's support for points of interest on the map associated with quests, the API functions are:
 * new QuestMapUpdateQuest(index) -- Is 'index' the normal quest log index? [1]
 * new QuestMapGetQuestName(index) [1]
 * new QuestMapGetPOIInfoForQuest(questIndex, poiIndex) [1]

Quest API

 * undocumented GetAbandonedQuestName
 * undocumented GetAbandonQuestItems
 * undocumented GetQuestLogSpellLink

Casting Events
Spell casting events and queries indicate whether enemy spells/channeling can be interrupted:
 * new UNIT_SPELLCAST_INTERRUPTIBLE [1]
 * new UNIT_SPELLCAST_NOT_INTERRUPTIBLE [1]

Casting Functions

 * updated UnitCastingInfo(unit) -- added interrupt result [1]
 * updated UnitChannelInfo(unit) -- added interrupt result [1]

Calendar Functions

 * updated CalendarGetDayEvent
 * new CalendarGetDayEventSequenceInfo

Mail functions

 * updated GetInboxNumItems -- added totalItems

Gamemaster Functions

 * new GMResponseNeedMoreHelp(text)

Loot Trading/Refunding

 * new END_REFUND -- triggered when a returnable item's refund period ends (or maybe would end if action performed?) [1]
 * new END_BOUND_TRADEABLE -- Not 100% sure of this is the right event name [1]
 * new EndBoundTradeable(someVar) -- inferred from staticPopupDialogs.lua [1]
 * new GetSocketItemBoundTradeable [4]

Other Information

 * new GetPlayerInfoByGUID("guid") - Returns basic information about another player from their GUID [1]
 * new FillLocalizedClassList(table, boolean)
 * new IsXPUserDisabled
 * new CanQueueForWintergrasp
 * updated IsFlyableArea -- updated to work properly in dalaran (returning 1 in Karsus landing) [5]

Combatlog Events

 * updated COMBAT_LOG_EVENT

ChatLog Events

 * new UPDATE_CHAT_COLOR_NAME_BY_CLASS [4]

Inventory Events

 * new EQUIPMENT_SWAP_FINISHED [1]

Unit Events

 * new UNIT_DISSIPATES

GameMaster Events

 * new GMRESPONSE_RECEIVED

Battlefield Events

 * new BATTLEFIELD_MGR_QUEUE_REQUEST_RESPONSE
 * new BATTLEFIELD_MGR_QUEUE_INVITE
 * new BATTLEFIELD_MGR_ENTRY_INVITE
 * new BATTLEFIELD_MGR_EJECT_PENDING
 * new BATTLEFIELD_MGR_EJECTED
 * new NPC_PVPQUEUE_ANYWHERE

Reputation Events

 * new ENABLE_XP_GAIN
 * new DISABLE_XP_GAIN