Some refactorings:

- Overrides added
 - usages of push_back() replaced with emplace_back()
 - Loop variable made const-refernce
 - NULL replaced with nullptr
 - Names used in the declaration and definition unified
 - size() replaced with empty
 - Identical cases merged

include/internal/catch_test_case_tracker.cpp

@@ -225,8 +225,8 @@ namespace TestCaseTracking {
     void SectionTracker::addInitialFilters( std::vector<std::string> const& filters ) {
         if( !filters.empty() ) {
             m_filters.reserve( m_filters.size() + filters.size() + 2 );
-            m_filters.push_back(""); // Root - should never be consulted
-            m_filters.push_back(""); // Test Case - not a section filter
+            m_filters.emplace_back(""); // Root - should never be consulted
+            m_filters.emplace_back(""); // Test Case - not a section filter
             m_filters.insert( m_filters.end(), filters.begin(), filters.end() );
         }
     }