Removes reference to register_uninstall_hook from code comment

Perhaps mention uninstall.php in stead?

```
// Register hooks that are fired when the plugin is activated or deactivated.
// When the plugin is deleted, the uninstall.php file is loaded.
```
Mention uninstall.php in code comment
Removes 'Change 'plugin-name' to the name of your plugin' from DocBlock

Removes 'Change 'plugin-name' to the name of your plugin' from add_plugin_admin_menu() function DocBlock, as this is now defined via a variable.
Replace plugin-name with $this->plugin_slug in add_action_links()
Merge pull request #79 from barryceelen/patch-2

Removes 'Change 'plugin-name' to the name of your plugin' from DocBlock
Merge pull request #80 from barryceelen/patch-3

Replace plugin-name with $this->plugin_slug in add_action_links()
Merge pull request #77 from barryceelen/patch-1

Removes reference to register_uninstall_hook from code comment
Place options page under 'Settings' in stead of 'Plugins' menu
Merge pull request #81 from barryceelen/patch-1

Place options page under 'Settings' in stead of 'Plugins' menu
Update $plugin_slug comment

The boilerplate uses the variable name when internationalizing strings, where the comment on $plugin_slug says to do the opposite.
Merge pull request #82 from barryceelen/patch-1

Update $plugin_slug comment
Add admin class
Update inline documentation
Move function lower down
Merge pull request #86 from grappler/master

Add admin class
Moving the screenshot to the assets directory

Related #89
updating the javascript to include more whitespace as per the wordpress javascript coding standards
adding a 'GitHub Plugin URI' to the wordpress-plugin header

Fixes #75
defining a section to provide links for recommended tools
Update README.txt

Add additional possible installation methods