Bug #902 - 'task version' requires a .taskrc

- Added special case support for '--version' which bypasses all
  configuration.  Not documented.  For extension prgorams like
  'taskhelm', that need to determine whether taskwarrior is
  sufficiently current.

src/main.cpp

@@ -46,6 +46,7 @@ Context context;
 #define srand(x) srandom(x)
 #endif
 
+////////////////////////////////////////////////////////////////////////////////
 int main (int argc, const char** argv)
 {
   // Set up randomness.
@@ -59,6 +60,12 @@ int main (int argc, const char** argv)
 
   int status = 0;
 
+  if (argc == 2 && !strcmp (argv[1], "--version"))
+  {
+    std::cout << VERSION << "\n";
+  }
+  else
+  {
     try
     {
       status = context.initialize (argc, argv);
@@ -77,6 +84,7 @@ int main (int argc, const char** argv)
       std::cerr << STRING_UNKNOWN_ERROR << "\n";
       status = -2;
     }
+  }
 
   return status;
 }