Stopping attempt to perform Skill Update unless connected to the internet

Stopping attempt to perform Skill Update unless connected to the internet.  Also added translatable versions of spoken messages.

mycroft/res/text/en-us/checking for updates.dialog

@@ -0,0 +1,2 @@
+Checking for updates
+Just a moment while I update myself

mycroft/res/text/en-us/no network connection.dialog

@@ -0,0 +1,3 @@
+I don't seem to be connected to the internet
+I can't reach the internt right now
+Unable to connect to the internet

mycroft/res/text/en-us/skills updated.dialog

@@ -0,0 +1,2 @@
+I'm up to date now
+Skills Updated.  I'm ready to help you.

mycroft/skills/main.py

@@ -35,6 +35,7 @@ from mycroft.skills.core import load_skill, create_skill_descriptor, \
 from mycroft.skills.intent_service import IntentService
 from mycroft.util import connected
 from mycroft.util.log import getLogger
+import mycroft.dialog
 
 # ignore DIGCHLD to terminate subprocesses correctly
 signal.signal(signal.SIGCHLD, signal.SIG_IGN)
@@ -66,10 +67,10 @@ def install_default_skills(speak=True):
         t = p.communicate()[0]
         if t.splitlines()[-1] == "Installed!" and speak:
             ws.emit(Message("speak", {
-                'utterance': "Skills Updated. Mycroft is ready"}))
+                'utterance': mycroft.dialog.get("skills updated")}))
         elif not connected():
             ws.emit(Message("speak", {
-                'utterance': "Check your network connection"}))
+                'utterance': mycroft.dialog.get("no network connection")}))
 
     else:
         logger.error("Unable to invoke Mycroft Skill Manager: " + MSM_BIN)
@@ -78,14 +79,15 @@ def install_default_skills(speak=True):
 def skills_manager(message):
     global skills_manager_timer, ws
 
-    if skills_manager_timer is None:
-        # TODO: Localization support
-        ws.emit(
-            Message("speak", {'utterance': "Checking for Updates"}))
+    if connected():
+        if skills_manager_timer is None:
+            ws.emit(
+                Message("speak", {'utterance':
+                        mycroft.dialog.get("checking for updates")}))
 
-    # Install default skills and look for updates via Github
-    logger.debug("==== Invoking Mycroft Skill Manager: " + MSM_BIN)
-    install_default_skills(False)
+        # Install default skills and look for updates via Github
+        logger.debug("==== Invoking Mycroft Skill Manager: " + MSM_BIN)
+        install_default_skills(False)
 
     # Perform check again once and hour
     skills_manager_timer = Timer(3600, _skills_manager_dispatch)