experience points calculation
Ignore Xcode project/workspace user data
Fix Xcode build

* added OpenGL framework to libraries
* removed dubious header search path pointing to an absolute path
inside Xcode.app
MacPorts support for Xcode build

* added MacPorts library and include paths to search path
* updated build instructions in README to explain how to install
dependencies with MacPorts
Fix for issue #771 (Psi attack breaking targeting mode).
fix incorrect craft rearming
fix explosions
Fix BR 779
Update CraftArmorState.cpp
Update SoldierArmorState.cpp
Update SavedGame.cpp
Update SavedGame.h
Fixed listed detections in Base Info screen
Merge pull request #920 from FalkoOXC/QickArmourSelection

Qick armour selection
Compilers
Merge pull request #915 from sfalexrog/fixes

Fix for issue #771 (Psi attack breaking targeting mode).
center camera
Merge pull request #916 from redv/fix_craft_reloading

Fix: incorrect rearming of Craft weapons
Merge pull request #902 from hackbunny/xcode_building

Basic Xcode build improvements
Merge pull request #897 from redv/experience_calc

Perfectionism: experience points calculation