Add zoom command

src/excmds.ts

@@ -182,6 +182,13 @@ export function clicknext(dir = "next"){
     // Stops us from having to hardcode in RPS and reddit, for example.
     window.location.href = nextlinks.slice(-1)[0].href
 }
+
+//#background
+export function zoom(level=0){
+    level = level > 3 ? level / 100 : level
+    browser.tabs.setZoom(level)
+}
+
 // }}}
 
 // {{{ TABS

src/tridactyl.d.ts

@@ -20,3 +20,8 @@ interface Window {
 declare namespace browser.find {
     function find(query, object): any
 }
+
+// setZoom has an optional first argument of tabId. Unclear how first argument can be optional.
+declare namespace browser.tabs {
+    function setZoom(number): any
+}