drop JSON_VALUE_USE_INTERNAL_MAP, JSON_USE_SIMPLE_INTERNAL_ALLOCATOR

And remove some old headers.

These were not actually compiling anymore, and there were outstanding,
known bugs, e.g. https://sourceforge.net/p/jsoncpp/bugs/27
diff --git a/doc/doxyfile.in b/doc/doxyfile.in
index bb30c35..57c61c2 100644
--- a/doc/doxyfile.in
+++ b/doc/doxyfile.in
@@ -1946,8 +1946,7 @@
 PREDEFINED             = "_MSC_VER=1400" \
                          _CPPRTTI \
                          _WIN32 \
-                         JSONCPP_DOC_EXCLUDE_IMPLEMENTATION \
-                         JSON_VALUE_USE_INTERNAL_MAP
+                         JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The
diff --git a/doc/web_doxyfile.in b/doc/web_doxyfile.in
index 8df2d8b..07d6819 100644
--- a/doc/web_doxyfile.in
+++ b/doc/web_doxyfile.in
@@ -1946,8 +1946,7 @@
 PREDEFINED             = "_MSC_VER=1400" \
                          _CPPRTTI \
                          _WIN32 \
-                         JSONCPP_DOC_EXCLUDE_IMPLEMENTATION \
-                         JSON_VALUE_USE_INTERNAL_MAP
+                         JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The