Update READMEs -

       * update individual project READMEs
       * add third-party licenses & copyright
       * add links to useful resources
Add #error directive to encourage API Key, Domain & App ID change by sample users.
Add Apache License, Version 2.0, update readme for UANotificaiton
Update project descriptions, fix UA license, fix absolute repo paths.
Merge pull request #1 from ideamonk/master

Update READMEs and add #error directive to sample projects