Add detection for Chromium and fix inaccurate Ubuntu detection.

Closes #157.

Author: bnjmnt4n

platform.js

@@ -391,6 +391,7 @@
       { 'label': 'Opera Mini', 'pattern': 'OPiOS' },
       'Opera',
       { 'label': 'Opera', 'pattern': 'OPR' },
+      'Chromium',
       'Chrome',
       { 'label': 'Chrome Mobile', 'pattern': '(?:CriOS|CrMo)' },
       { 'label': 'Firefox', 'pattern': '(?:Firefox|Minefield)' },
@@ -972,6 +973,10 @@
         ua.indexOf('/' + data + '-') > -1) {
       os = trim(os.replace(data, ''));
     }
+    // Ensure OS does not include the browser name.
+    if (os && os.indexOf(name) != -1 && !RegExp(name + ' OS').test(os)) {
+      os = os.replace(RegExp(' *' + qualify(name) + ' *'), '');
+    }
     // Add layout engine.
     if (layout && !/\b(?:Avant|Nook)\b/.test(name) && (
         /Browser|Lunascape|Maxthon/.test(name) ||

test/test.js

@@ -628,6 +628,14 @@
       'os': 'iOS 4.3+'
     },
 
+    'Chromium 66.0.3359.181 on Ubuntu 64-bit': {
+      'ua': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/66.0.3359.181 Chrome/66.0.3359.181 Safari/537.36',
+      'layout': 'Blink',
+      'name': 'Chromium',
+      'os': 'Ubuntu 64-bit',
+      'version': '66.0.3359.181'
+    },
+
     'Electron 1.4.5 (Chromium 53.0.2785.113; Node 6.5.0) on Windows 10 64-bit': {
       'ua': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) electron-app/1.0.0 Chrome/53.0.2785.113 Electron/1.4.5 Safari/537.36',
       'global': {},