Clean up config file format, modify how projects are launched, and add broken theme setting handling

tests/reference/baseConfig_novelwriter.conf

@@ -1,27 +1,32 @@
+[Meta]
+timestamp = 2022-11-10 11:10:10
+
 [Main]
-timestamp = 2022-10-26 11:19:49
 theme = default
 syntax = default_light
-guifont = 
-guifontsize = 11
-lastnotes = 0x0
-guilang = en_GB
+font = 
+fontsize = 11
+localisation = en_GB
 hidevscroll = False
 hidehscroll = False
+lastnotes = 0x0
+lastpath = /home/vkbo
 
 [Sizes]
-geometry = 1200, 650
+mainwindow = 1200, 650
 preferences = 700, 615
-projcols = 200, 60, 140
+projloadcols = 280, 60, 160
 mainpane = 300, 800
 viewpane = 500, 150
 outlinepane = 500, 150
-fullscreen = False
 
 [Project]
 autosaveproject = 60
 autosavedoc = 30
 emphlabels = True
+backuppath = 
+backuponclose = False
+askbeforebackup = True
 
 [Editor]
 textfont = None
@@ -61,12 +66,8 @@ highlightemph = True
 stopwhenidle = True
 useridletime = 300
 
-[Backup]
-backuppath = 
-backuponclose = False
-askbeforebackup = True
-
 [State]
+fullscreen = False
 showrefpanel = True
 viewcomments = True
 viewsynopsis = True
@@ -77,6 +78,3 @@ searchloop = False
 searchnextfile = False
 searchmatchcap = False
 
-[Path]
-lastpath = 
-