merge PR and added several examples

merged in PR #7
added examples:

• create site
• delete site
• modify WLAN settings for controller version 5.5.X and higher using the set_device_settings_base() method, also demonstrates the use of get_last_results_raw()

API client class v1.1.23

• minor code cleanup and input validation/sanitization improvements
• added delete_device() function/method
• added move_device() function/method
• added optional type parameter to stat_sessions()
• updated README

API client class v1.1.22

fixed issue #2 caused by a typo with "if (in_array()...", thanks go to @LuFlo for catching that

API client class v1.1.21

• minor code clean up
• added archive_alarm() function/method

API client class v1.1.20: fixed typo in list_known_rogueaps()

fixed typo in list_known_rogueaps()

API client class v1.1.19: addition of several new functions/methods and minor code cleanup

• added list_known_rogueaps() function/method
• added stat_status() function/method
• added power_cycle_switch_port() function/method

API client class v1.1.18: code optimization, improved parameter validation and debug messages

• removed repetitive code (json_decode and $this>baseurl)
• added capture of JSON decoding errors when debug = true
• use intval() on function/method parameters which must be an integer
• further parameter validation/checks

API client class version v1.1.17

added new functions for 5-minutes stats and minor code cleanup:

• added stat_5minutes_site() method/function
• added stat_5minutes_aps() method/function
• added optional parameter to list_dashboard() method/function to allow fetching of 5minutes stats

minor code cleanup and various changes

• added a 6th parameter to the constructor to enable SSL cert verification, recommended for production environments
• added examples/change_wlan_password.php to demonstrate WLAN password/PSK change
• updated main README accordingly

various tweaks and addition of a connection testing script to examples/

• more relaxed handling of $site in set_site(), now we only issue an error message when provided (short) site name is probably incorrect and debug mode is true
• added test_connection.php, a command line script which can be used to quickly test the connection to your controller with various cURL options which you can quickly change