Add basic session management to avoid login each time

app/src/main/java/im/vector/riotredesign/features/login/LoginActivity.kt

@@ -23,6 +23,7 @@ class LoginActivity : RiotActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_login)
         authenticateButton.setOnClickListener { authenticate() }
+        checkActiveSessions()
     }
 
     private fun authenticate() {
@@ -48,6 +49,13 @@ class LoginActivity : RiotActivity() {
         })
     }
 
+    private fun checkActiveSessions() {
+        if (authenticator.hasActiveSessions()) {
+            matrix.currentSession = authenticator.getLastActiveSession()
+            goToHomeScreen()
+        }
+    }
+
     private fun goToHomeScreen() {
         val intent = HomeActivity.newIntent(this)
         startActivity(intent)