Rename onChangeHealth/Mana to onMana/HealthChange

The event name in creatures.xml also changed from:
changehealth and changemana to healthchange and manachange

If you were utilizing any of these creature events, you must update
their names for them to function.
Remove unreachable code

It was causing a warning when compiling in Visual Studio. If another
compiler for Windows complains, it may be added back with a preprocessor
conditional for that compiler.
Player:onGain/LoseExperience events

Closes #910
Fix Player:onGain/LoseExperience events
Visual Studio OBJ files now go in their own directory.

Fixes #874
Add Game.broadcastMessage
Move broadcastMessage to compat.lua
Add scripting reference to README
doPlayerRemoveItem to compat

getThingPos to compat

getHouseByPlayerGUID to compat

shortened getThingPos

getThingPos fixes

fix typo