Added included domains (whitelist).

Internal rewrite to improve the functionality. No changes in the settings storage.

Bug: wrong currency was shown in the popup.

Bug: prices in the same element were converted repeatedly.

Bug: drag and drop on touchscreen did not work.

ISO 4217 amendments 166 to 169 included. Notably the latest Venezolan currency, VES, is added.

Updated the external libraries jQuery, jQuery UI, jQuery UI Touch-Punch, DOM Purify.

Three different currency data sources to choose from, instead of only one.
Link to currencies test page.
Updates from ISO 4217 amendments: São Tomé and Príncipe STN, Mauritania MRU, and new name for Philippine piso.
Pounds are not converted any more.
A$ is converted as AUD.
Internal change: updated jQuery, jQuery UI, and introduced DOMPurify for checking input data.