add Xcode gitignore
add Xcode gitignore

treehopper-electronics/treehopper-sdk,treehopper-electronics/treehopper-sdk,treehopper-electronics/treehopper-sdk,treehopper-electronics/treehopper-sdk,treehopper-electronics/treehopper-sdk,treehopper-electronics/treehopper-sdk