Adds virtual destructors for various interface classes.

Machines/AppleII/Card.hpp

@@ -39,6 +39,7 @@ namespace AppleII {
 */
 class Card {
 	public:
+		virtual ~Card() {}
 		enum Select: int {
 			None	= 0,		// No select line is active
 			IO		= 1 << 0,	// IO select is active

Machines/MSX/ROMSlotHandler.hpp

@@ -43,6 +43,8 @@ class MemoryMap {
 
 class ROMSlotHandler {
 	public:
+		virtual ~ROMSlotHandler() {}
+
 		/*! Advances time by @c half_cycles. */
 		virtual void run_for(HalfCycles half_cycles) {}
 

Machines/Utility/Typer.hpp

@@ -26,6 +26,8 @@ class CharacterMapper {
 		/// @returns The EndSequence-terminated sequence of keys that would cause @c character to be typed.
 		virtual uint16_t *sequence_for_character(char character) = 0;
 
+		virtual CharacterMaper() {}
+
 	protected:
 		typedef uint16_t KeySequence[16];
 

Storage/Disk/Encodings/MFM/Encoder.cpp

@@ -19,6 +19,7 @@ using namespace Storage::Encodings::MFM;
 class MFMEncoder: public Encoder {
 	public:
 		MFMEncoder(std::vector<bool> &target) : Encoder(target) {}
+		virtual ~MFMEncoder() {}
 
 		void add_byte(uint8_t input) {
 			crc_generator_.add(input);

Storage/Disk/Track/Track.hpp

@@ -70,6 +70,8 @@ class HeadPosition {
 */
 class Track {
 	public:
+		virtual ~Track() {}
+
 		/*!
 			Describes the location of a track, implementing < to allow for use as a set key.
 		*/