Better parsing of M/Counter

Mimetype may contain a parameters.
Then, the mimetype would be something like "text/html;foo=bar;foz=baz"

It will contains a `;` and `=` and it conflicts with the same operators
we use to separate the items in our list.

We have to use a more advanced algorithm which takes the context into
account.

Fix #416

src/tools/stringTools.cpp

@@ -268,7 +268,8 @@ std::string kiwix::urlDecode(const std::string& value, bool component)
 /* Split string in a token array */
 std::vector<std::string> kiwix::split(const std::string& str,
                                       const std::string& delims,
-                                      bool trimEmpty)
+                                      bool trimEmpty,
+                                      bool keepDelim)
 {
   std::string::size_type lastPos = 0;
   std::string::size_type pos = 0;
@@ -279,6 +280,9 @@ std::vector<std::string> kiwix::split(const std::string& str,
     if (!trimEmpty || !token.empty()) {
       tokens.push_back(token);
     }
+    if (keepDelim) {
+      tokens.push_back(str.substr(pos, 1));
+    }
     lastPos = pos + 1;
   }