Code Cleanup

- Constify some catches.

src/TDB2.cpp

@@ -319,7 +319,7 @@ void TF2::load_tasks ()
     _loaded_tasks = true;
   }
 
-  catch (std::string& e)
+  catch (const std::string& e)
   {
     throw e + format (STRING_TDB2_PARSE_ERROR, _file._data, line_number);
   }

src/commands/CmdEdit.cpp

@@ -811,7 +811,7 @@ ARE_THESE_REALLY_HARMFUL:
       parseTask (task, after, dateformat);
     }
 
-    catch (std::string& e)
+    catch (const std::string& e)
     {
       problem = e;
       oops = true;

src/commands/CmdMerge.cpp

@@ -97,7 +97,7 @@ int CmdMerge::execute (std::string& output)
     {
         context.tdb2.merge (file);
     }
-    catch (std::string& e) {
+    catch (const std::string& e) {
         if (e == STRING_TDB2_UP_TO_DATE)
         {
             output += e + "\n";

src/commands/CmdShell.cpp

@@ -111,7 +111,7 @@ int CmdShell::execute (std::string&)
         context.run ();
       }
 
-      catch (std::string& error)
+      catch (const std::string& error)
       {
         std::cerr << error << "\n";
       }

src/main.cpp

@@ -74,7 +74,7 @@ int main (int argc, const char** argv)
         status = context.run ();
     }
 
-    catch (std::string& error)
+    catch (const std::string& error)
     {
       std::cerr << error << "\n";
       status = -1;