explicit all single param constructors

Author: bertmelis

src/GWG/GWG.h

@@ -41,7 +41,7 @@ class GWG {
   explicit GWG(const char* interface);
   #endif
   template<class C>
-  GWG(C* interface)
+  explicit GWG(C* interface)
   : _state(State::UNDEFINED)
   , _currentMillis(vw_millis())
   , _lastMillis(_currentMillis)

src/VS1/VS1.h

@@ -41,7 +41,7 @@ class VS1 {
   explicit VS1(const char* interface);
   #endif
   template<class C>
-  VS1(C* interface)
+  explicit VS1(C* interface)
   : _state(State::UNDEFINED)
   , _currentMillis(vw_millis())
   , _lastMillis(_currentMillis)