multiple improvements to logging

- added style.log table
- removed contextmenu
- use ctrl+click to copy individual log entries
- use icon instead of + or - for log items in logview

data/core/command.lua

@@ -64,7 +64,7 @@ end
 function command.add_defaults()
   local reg = {
     "core", "root", "command", "doc", "findreplace",
-    "files", "drawwhitespace", "dialog"
+    "files", "drawwhitespace", "dialog", "log"
   }
   for _, name in ipairs(reg) do
     require("core.commands." .. name)