First draft of iOS standalone apps study
Merge branch 'io_standalone' of https://github.com/w3c-webmob/installable-webapps into io_standalone

* 'io_standalone' of https://github.com/w3c-webmob/installable-webapps:
  renamed file
  Compressed images, cleaned up text
  Typos and links
  Markdown fixes
  First draft of iOS standalone apps study