Updates to plugin.xml and readme related to lib installations (mostly).

Hi there after a long while. I did some modifications to the last version of the plugin:

- Patrick Heneise somehow assumed ownership to your plugin by basically changing the author and package name for the plugin. I reverted that to your name, you should be having the credit for the plugin, not the people (like me) who forked and changed a thing or two.
- Although you say Flurry doesn't allow distributing their libs (which is a good choice imho), the plugin mechanism assumes it was distributed and asks manually downloads to plugin folder, which is error prone. Instead, I removed the installation of flurry libs from the plugin mechanism, and added necessary steps and documentation to readme.

Also did some minor changes here and there, tested it in Android, it's working fine. I will also test in iOS later on.