Make the allowed SSL Ciphers a protocol option for CurlFile.

Recent versions of libcurl disable the RC4-SHA cipher that is still used by some sites.
While certainly the right decision, it breaks (at least) the YouTube addon.

This patch allows addons to explicitly request disabled ciphers via a protocol option:
https://host/path|SSLCipherList=DEFAULT:RC4-SHA
Merge pull request #4489 from Orochimarufan/sslcipher

Make the allowed SSL Ciphers a protocol option for CurlFile.
[depends] move ffmpeg to unified deps
[configure] remove internal ffmpeg
remove ffmpeg from tree
ffmpeg: remove dll wrappers
add ffmpeg lock manager
todo: refactor to own file
ffmpeg: move callbacks into separate file
remove ffmpeg dlls from generated headers
not removing win32 as this might still be needed?
sq to configure - add --with-ffmpeg=force option
this will always build our ffmpeg version, even if its found in system
only enable auto building ffmpeg if we are not cross compiling
[rpi] setup-sdk.sh: allow overriding of buildroot and xbmc install paths
also don't require root if not needed
sq to configure - fixup after upstream rebase
add ffmpeg makefile for rpi
sq to configure - unset PKG_CONFIG_SYSROOT_DIR when getting FFMPEG_LIBDIR
sq to setup-sdk.sh - fix sudo needs detection
bump ffmpeg
sq to depends - add a single file to specify our ffmpeg version
sq to rpi ffmpeg makefile - use FFMPEG-VERSION file
sq to configure - use FFMPEG-VERSION file in autobuild.sh