fix reading of doubles. There may be a + after the e

Stream_support/include/CGAL/IO/io.h

@@ -132,7 +132,7 @@ public:
 	break;
       }
       c = static_cast<char_type>(i);
-      if(std::isdigit(c) || (c =='.') || (c =='E') || (c =='e') || (c =='-')){
+      if(std::isdigit(c) || (c =='.') || (c =='E') || (c =='e') || (c =='+') || (c =='-')){
         buffer += c;
       }else{
 	is.unget();

Stream_support/test/Stream_support/data/double.txt

@@ -0,0 +1,4 @@
++1.2e+3 45 12
++1.2e03 45 12
++1.2e003 45 12
+-1.2e03 45 12

Stream_support/test/Stream_support/double.cpp

@@ -0,0 +1,14 @@
+#include <iostream>
+#include <fstream>
+#include <CGAL/Simple_cartesian.h>
+
+
+int main()
+{
+  std::ifstream in("data/double.txt");
+  CGAL::Simple_cartesian<double>::Point_3 p;
+  while(in >> p){
+    std::cout << p << std::endl;
+  }
+  return 0;
+}