Merge pull request #2255 from shadyproject/plugin/xcode-support

basic command line xcode functionality

plugins/xcode/xcode.plugin.zsh

+#xc function courtesy of http://gist.github.com/subdigital/5420709
+function xc {
+  xcode_proj=`find . -name "*.xc*" -d 1 | sort -r | head -1`
+  if [[ `echo -n $xcode_proj | wc -m` == 0 ]]
+  then
+    echo "No xcworkspace/xcodeproj file found in the current directory."
+  else
+    echo "Found $xcode_proj" 
+    open "$xcode_proj" 
+  fi
+}
+
+function xcsel {
+  sudo xcode-select --switch "$*"
+}
+
+alias xcb='xcodebuild'
+alias xcp='xcode-select --print-path'