added undocumented /d2Zi+ compiler flag to _win-vs11/Release.props

brings better release builds debugging experience
added .gitattributes, normalized EOLs
print total elapsed time at the end of PackedArraySelfBench and PackedArraySIMDSelfBench
changed iOS deployment target to 7.0 and added arm64 architecture to Xcode project
added xcshareddata/ to .gitignore
updated README

updated oneliner to compile to iOS from CLI with latest iOS SDK