fix a bug where `rake' command would re-launch an iOS 7 simulator every time
fix a bug where `rake' command would re-launch an iOS 7 simulator every time

iOS 7 has only retina simulator and com.apple.iphonesimulator indicates "iPhone Retina (4-inch)" as default.
So, we need to use retina even if it does not configure ENV['retina']

beni55/RubyMotion,incbee/RubyMotion,katsuyoshi/RubyMotion,HipByte/RubyMotion,beni55/RubyMotion,jjaffeux/RubyMotion,incbee/RubyMotion,incbee/RubyMotion,beni55/RubyMotion,katsuyoshi/RubyMotion,HipByte/RubyMotion,katsuyoshi/RubyMotion,katsuyoshi/RubyMotion,beni55/RubyMotion,jjaffeux/RubyMotion,HipByte/RubyMotion,hboon/RubyMotion,hboon/RubyMotion,incbee/RubyMotion,jjaffeux/RubyMotion,hboon/RubyMotion,jjaffeux/RubyMotion