WebUI: make API locale independet

Sizes are now given in bytes.
Dates are Unix timestamps and converted to ISO 8601 in the web UI.
Numbers are not converted to strings.
-1 is returned for undefined values.

Some keys have been splitted:

Torrent list (json/torrents)
 * num_seeds: Torrent seeds connected to
 * num_complete: Torrent seeds in the swarm
 * num_leechs: Torrent leechers connected to
 * num_incomplete: Torrent leechers in the swarm

Torrent generic properties (propertiesGeneral/hash)
 * total_uploaded: Total data uploaded
 * total_uploaded_session: Total data uploaded this session
 * total_downloaded: Total data dowloaded
 * total_downloaded_session: Total data downloaded this session
 * time_elapsed: Torrent elapsed time
 * seeding_time: Torrent elapsed time while complete
 * nb_connections: Torrent connection count
 * nb_connections_limit: Torrent connection count limit

Global transfer info (json/transferInfo)
 * dl_info_speed: Global downalod rate
 * dl_info_data: Data downloaded this session
 * up_info_speed: Global upload rate
 * up_info_data: Data uploaded this session

Closes #1524.

src/webui/www/public/scripts/misc.js

@@ -0,0 +1,78 @@
+/*
+ * JS counterpart of the function in src/misc.cpp
+ */
+function friendlyUnit(value, isSpeed) {
+  units = [
+    "_(B)",
+    "_(KiB)",
+    "_(MiB)",
+    "_(GiB)",
+    "_(TiB)",
+  ];
+
+  if (value < 0)
+    return "_(Unknown)";
+  var i = 0;
+  while (value >= 1024. && i++ < 6)
+    value /= 1024.;
+  var ret;
+  if (i == 0)
+    ret = value.toFixed(2) + " " + units[0];
+  else
+    ret = value.toFixed(2) + " " + units[i];
+  if (isSpeed)
+    ret += "_(/s)";
+  return ret;
+}
+
+/*
+ * JS counterpart of the function in src/misc.cpp
+ */
+function friendlyDuration(seconds) {
+  var MAX_ETA = 8640000;
+  if (seconds < 0 || seconds >= MAX_ETA)
+    return "∞";
+  if (seconds == 0)
+    return "0";
+  if (seconds < 60)
+    return "< " + "_(%1m)".replace("%1", "1"); //translation of "< 1m" not working
+  var minutes = seconds / 60;
+  if (minutes < 60)
+    return "_(%1m)".replace("%1", parseInt(minutes));
+  var hours = minutes / 60;
+  minutes = minutes - hours*60;
+  if (hours < 24)
+    return "_(%1h %2m)".replace("%1", parseInt(hours)).replace("%2", parseInt(minutes))
+  var days = hours / 24;
+  hours = hours - days * 24;
+  if (days < 100)
+    return "_(%1d %2h)".replace("%1", parseInt(days)).replace("%2", parseInt(hours))
+  return "∞";
+}
+
+/*
+ * From: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString
+ */
+if (!Date.prototype.toISOString) {
+  (function() {
+
+    function pad(number) {
+      if (number < 10) {
+        return '0' + number;
+      }
+      return number;
+    }
+
+    Date.prototype.toISOString = function() {
+      return this.getUTCFullYear() +
+        '-' + pad(this.getUTCMonth() + 1) +
+        '-' + pad(this.getUTCDate()) +
+        'T' + pad(this.getUTCHours()) +
+        ':' + pad(this.getUTCMinutes()) +
+        ':' + pad(this.getUTCSeconds()) +
+        '.' + (this.getUTCMilliseconds() / 1000).toFixed(3).slice(2, 5) +
+        'Z';
+    };
+
+  }());
+}