Added theme setting to config file

nw/config.py

@@ -126,6 +126,12 @@ class Config:
 
         # Get options
 
+        ## Main
+        cnfSec = "Main"
+        if confParser.has_section(cnfSec):
+            if confParser.has_option(cnfSec,"theme"):
+                self.guiTheme = confParser.get(cnfSec,"theme")
+
         ## Sizes
         cnfSec = "Sizes"
         if confParser.has_section(cnfSec):
@@ -204,6 +210,7 @@ class Config:
         cnfSec = "Main"
         confParser.add_section(cnfSec)
         confParser.set(cnfSec,"timestamp", datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
+        confParser.set(cnfSec,"theme",     str(self.guiTheme))
 
         ## Sizes
         cnfSec = "Sizes"

sample/sampleNovel/nwProject.nwx

@@ -1,5 +1,5 @@
 <?xml version='1.0' encoding='utf-8'?>
-<novelWriterXML appVersion="0.1.3" fileVersion="1.0" timeStamp="2019-05-18 19:40:13">
+<novelWriterXML appVersion="0.1.3" fileVersion="1.0" timeStamp="2019-05-18 20:51:40">
   <project>
     <name>Sample Project</name>
     <title>Sample Project</title>

tests/reference/novelwriter.conf

@@ -1,5 +1,6 @@
 [Main]
 timestamp = 2019-05-18 15:06:44
+theme = default
 
 [Sizes]
 geometry = 1100, 650