Clean up README
PHP versions
Stub settings class
Fix typos in comments
#4 - add settings page to options menu
#4 - add settings sections
#4 - add settings fields
#4 - add comments with documentation
#4 - callback in scope of settings class
#4 - settings page markup
#4 - pass in field array as args
#4 - get options
#4 - add checkbox field type
#4 - register settings