Update to v101r19 release.

byuu says:

Changelog:

-   added \~130 new PAL games to icarus (courtesy of Smarthuman
    and aquaman)
-   added all three Korean-localized games to icarus
-   sfc: removed SuperDisc emulation (it was going nowhere)
-   sfc: fixed MSU1 regression where the play/repeat flags were not
    being cleared on track select
-   nall: cryptography support added; will be used to sign future
    databases (validation will always be optional)
-   minor shims to fix compilation issues due to nall changes

The real magic is that we now have 25-30% of the PAL SNES library in
icarus!

Signing will be tricky. Obviously if I put the public key inside the
higan archive, then all anyone has to do is change that public key for
their own releases. And if you download from my site (which is now over
HTTPS), then you don't need the signing to verify integrity. I may just
put the public key on my site on my site and leave it at that, we'll
see.

nall/string/core.hpp

@@ -30,6 +30,26 @@ template<typename... P> auto string::assign(P&&... p) -> string& {
   return append(forward<P>(p)...);
 }
 
+template<typename T, typename... P> auto string::prepend(const T& value, P&&... p) -> string& {
+  prepend(forward<P>(p)...);
+  return _prepend(make_string(value));
+}
+
+template<typename... P> auto string::prepend(const nall::string_format& value, P&&... p) -> string& {
+  prepend(forward<P>(p)...);
+  return format(value);
+}
+
+auto string::prepend() -> string& {
+  return *this;
+}
+
+template<typename T> auto string::_prepend(const stringify<T>& source) -> string& {
+  resize(source.size() + size());
+  memory::move(get() + source.size(), get(), size() - source.size());
+  memory::copy(get(), source.data(), source.size());
+}
+
 template<typename T, typename... P> auto string::append(const T& value, P&&... p) -> string& {
   _append(make_string(value));
   return append(forward<P>(p)...);