Make "like" links one way

- Updated dolike() function to accept a "un-" switch
- [frio] Updated doLikeAction() function to call dolike() instead of having duplicated code
- Added boolean logic (with explanatory truth table) to smartly delete existing activities in Model\Item::performActivity
- Moved verb/activity parameter handling closer to their use in Model\Item::performActivity
- Updated all references to dolike() and doLikeAction() to include the "un-" switch

view/js/main.js

@@ -649,9 +649,15 @@ function imgdull(node) {
 // trickery. This still could cause confusion if the "like" ajax call
 // is delayed and NavUpdate runs before it completes.
 
-function dolike(ident,verb) {
+/**
+ * @param {int}     ident The id of the relevant item
+ * @param {string}  verb  The verb of the action
+ * @param {boolean} un    Whether to perform an activity removal instead of creation
+ */
+function dolike(ident, verb, un) {
 	unpause();
 	$('#like-rotator-' + ident.toString()).show();
+	verb = un ? 'un' + verb : verb;
 	$.get('like/' + ident.toString() + '?verb=' + verb, NavUpdate);
 	liking = 1;
 	force_update = true;