Add support to configure install/upgrade messages (#1675)

Package Control.sublime-settings

@@ -60,6 +60,14 @@
 	// to the Sublime Text console
 	"debug": false,
 
+	// Print package install and upgrade messages.
+	// Valid values are:
+	// - "disabled": don't print anything
+	// - "background": open message view in background
+	// - "foreground": open message view in foreground
+	// - "auto": focus messages depending on command mode (unattended)
+	"print_messages": "auto",
+
 	// If package install, upgrade and removal info should be submitted to
 	// the channel for aggregated statistics
 	"submit_usage": true,

package_control/package_manager.py

@@ -114,6 +114,7 @@ def __init__(self):
             'package_destination',
             'package_name_map',
             'package_profiles',
+            'print_messages',
             'proxy_password',
             'proxy_username',
             'remove_orphaned',
@@ -2141,6 +2142,13 @@ def print_messages(self, package_name, package_dir, is_upgrade, old_version, new
             If ``True`` don't focus "Package Control Messages".
         """
 
+        if self.settings["print_messages"] == "disabled":
+            return
+        elif self.settings["print_messages"] == "background":
+            unattended = True
+        elif self.settings["print_messages"] == "foreground":
+            unattended = False
+
         try:
             messages_file = os.path.join(package_dir, 'messages.json')
             with open(messages_file, 'r', encoding='utf-8') as fobj: