(XDK) Build fixes
Build fix
(Menu) VERY WIP - Netplay options. Still lacks way to input a
name/IP address/port with a keyboard callback - also state
bringing up/teardown will need to be handled
(Menu) Split up keyboard input line cb code to separate file - menu_input_line_cb
(MSVC) Add new file
(Menu) You can now input nickname, IP address and TCP/UDP port
with the keyboard
(Menu) Add OSK enable option
(Menu) Make 'Save as Shader Preset' option available to non-HAVE_OSK targets as
well
Compile in rsound audio driver by default and make RSound
Server IP Address setting configurable by keyboard
Cleanups to keyboard callback stuff.
Fix shader preset save.

Have to take into consideration the preset type.
Repurpose RSound IP address setting.

It's hardcoded for RSound, but it's actually setting the generic audio device ...
Don't have to "save" key_event callback.

keyboard_line module already makes sure it works.
Add space for consistency.
Drop use of deprecated FFmpeg APIs.
Check for old libavutil version.
Allow retrieval of core_info_t for selected core.

Refactor a bit to avoid lots of duplicated
libretro_free_system_info/get_system_info, etc.
Also copy the core_info_t struct on core change.
Don't require display_info for core_info_list_get_info.
Fix Android build.

No idea how it built before (?!)
(Menu) Refactor file_list.c - move RMenu XUI code out of file_list.c
and into disp/rmenu_xui.cpp - have a custom 'external_list'
struct that display interfaces for the menu code can implement
optionally