Issue #23: Fixed error with HTTP Version number

added a try-catch to "stof" operation to catch errors with HTTP version number.

server_http.hpp

@@ -762,10 +762,17 @@ namespace SimpleWeb {
                 return;
               }
             }
-            if(std::stof(response->session->request->http_version) >= 1.1) {
-              auto new_session = std::make_shared<Session>(this->config.max_request_streambuf_size, response->session->connection);
-              this->read(new_session);
-              return;
+            try {
+              if(std::stof(response->session->request->http_version) >= 1.1) {
+                auto new_session = std::make_shared<Session>(this->config.max_request_streambuf_size, response->session->connection);
+                this->read(new_session);
+                return;
+              }
+            }
+            catch(const std::out_of_range& oor) {
+              std::cout << "HTTP Version number out of range" << oor.what() << std::endl;
+            } catch(const std::invalid_argument& ia) {
+              std::cout << "HTTP Version number invalid argument" << ia.what() << std::endl;
             }
           }
           else if(this->on_error)