Added check for updates to Datamaster constructor

Only runs once per session

@Datamaster/Datamaster.m

@@ -31,6 +31,33 @@
 
             % Get a list of Details and Channels that have been logged
             dm.updateDetails; dm.updateChannels;
+
+            %% Check for Updates - But Only once per session
+            persistent flagChecked
+            if isempty(flagChecked)
+                %Move to the Datamaster folder
+                savedCd = cd; cd(Datamaster.getPath);
+
+                %Fetch updates from remote
+                [success, ~] = system('git fetch');
+                assert(success==0, 'Error fetching updates from remote');
+
+                %Check Current Status
+                [success, str] = system('git status');
+                assert(success==0, 'Error reading git repo status');
+
+                %Get status
+                status = regexpi(str, 'Your branch is behind ''(.+)'' by (\d+)', 'tokens');
+
+                %Report to user
+                if ~isempty(status)
+                    warning(['Updates are avaliable. ',...
+                    'Run <a href="matlab:DatamasterSetup">Datamaster Setup</a> to Update']); 
+                end
+
+                %Return to original directory
+                cd(savedCd); flagChecked = true;
+            end
         end
 
         %% Small Public Methods -> Move externally if it grows