Introduce ini configuration file handling. This will be used for when xcrun needs to know specific information about a specified sdk or toolchain (i.e. what toolchain to use for a given sdk/platform, find out toolchain and sdk versions, ect). I was thinking about doing these in a plist format just as xcode does initially, but I figured an ini format is a better option because it adds less code complexity and is more portable (I don't feel like maintaining a local copy of CF-Lite just for these tools to process a couple of plists).