CAP-1329 cocoapod updates to docs and spec template

Updates to the cocopad docs and podspec template: 

* Updated README documentation
   * Update min iOS version and sample Artisan Version
   * remove references to --no-doc option, which doesn't exist anymore.
   * Simplify the ARManager startWithId instructions.
* Updated podspec template
   * Summary was too long (max 140 chars)
   * homepage unreachable
   * update documentation link
* Migrated the docs over to http://docs.useartisan.com/dev/ios-cocoapod-install/ (not merged yet maybe)