Replace C pointers and collections with C++ equivalents

Please note that the code hasn't been thoroughly examined/tested for memory leaks yet.

Changes:

• gboolean -> bool
• gchar* -> std::string
• gpointer chip -> Ptr<t_chip>
• gpointer chip_feature -> Ptr<t_chipfeature>
• GPtrArray -> std::vector
• t_chip* -> Ptr<t_chip>
• Remove @param comments describing just the parameter's data type
• GtkWidget *tachos[MAX_NUM_CHIPS][MAX_NUM_FEATURES] -> std::map
• Remove hard-coded limit on the maximum number of tachos
• Remove redundant field t_chip::num_features
• free_chip() -> t_chip::~t_chip()
• free_chipfeature() -> default auto-generated destructor
• new t_chip() -> xfce4::make<t_chip>()
• new t_chipfeature() -> xfce4::make<t_chipfeature>()
• for(;;) -> for(:)

Bug fixes:

• strncmp(disk, "/dev/fd", 6) -> xfce4::starts_with(disk, "/dev/fd")