Add API calls and stubs for filter matching and subscription management

shell/src/MatchesCommand.cpp

+#include <iostream>
+#include <sstream>
+
 #include "MatchesCommand.h"
 
-MatchesCommand::MatchesCommand() : Command("matches")
+MatchesCommand::MatchesCommand(AdblockPlus::FilterEngine& filterEngine)
+  : Command("matches"), filterEngine(filterEngine)
 {
 }
 
 void MatchesCommand::operator()(const std::string& arguments)
 {
+  std::istringstream argumentStream(arguments);
+  std::string url;
+  argumentStream >> url;
+  std::string contentType;
+  argumentStream >> contentType;
+  if (!url.size() || !contentType.size())
+  {
+    ShowUsage();
+    return;
+  }
+
+  if (filterEngine.Matches(url, contentType))
+    std::cout << "Match" << std::endl;
+  else
+    std::cout << "No match" << std::endl;
 }
 
 std::string MatchesCommand::GetDescription() const
 {
   return "Returns the first filter that matches the supplied URL";
 }
 
 std::string MatchesCommand::GetUsage() const
 {
-  return name + " URL";
+  return name + " URL CONTENT_TYPE";
 }