Bring most mimetypes in line with XDG specifications.  The following are not fully verified in source as of this commit due to ubiquity: html, empty, info, make, man, misc, source, unknown

diff --git a/BibleTime.tdevelop b/BibleTime.tdevelop
index 360895f..cf4e83c 100644
--- a/BibleTime.tdevelop
+++ b/BibleTime.tdevelop
@@ -210,7 +210,7 @@
       <type icon="" ext="h" name="C++ Header template" create="template" >
         <descr>BibleTime C++ header template</descr>
       </type>
-      <type icon="source_cpp" ext="cpp" name="C++ source file" create="template" >
+      <type icon="text-x-c++src" ext="cpp" name="C++ source file" create="template" >
         <descr>BibleTime C++ source template</descr>
       </type>
     </filetypes>