Revert "add new version of CommandLineParser. add empty docs"

This reverts commit 54a202b3d5.

Conflicts:
	modules/core/doc/command_line_parser.rst
	modules/core/include/opencv2/core/core.hpp
	modules/core/src/cmdparser.cpp
	modules/gpu/perf/main.cpp
	modules/gpu/test/main.cpp
	modules/ts/src/ts_perf.cpp

samples/cpp/demhist.cpp

@@ -62,7 +62,7 @@ static void help()
 
 const char* keys =
 {
-    "{@image|baboon.jpg|input image file}"
+    "{1| |baboon.jpg|input image file}"
 };
 
 int main( int argc, const char** argv )
@@ -70,7 +70,7 @@ int main( int argc, const char** argv )
     help();
 
     CommandLineParser parser(argc, argv, keys);
-    string inputImage = parser.get<string>(1);
+    string inputImage = parser.get<string>("1");
 
     // Load the source image. HighGUI use.
     image = imread( inputImage, 0 );