Start reverting new and broken YouTube subtitle code:

Revert "add '--write-srt' and '--srt-lang' aliases for backwards compatibility"

This reverts commit b9fc428494b22623529d364387b8693cc3cb1503.
Revert "Fixed typo in error message when no subtitles were available."

This reverts commit c0ba10467457a58e7198b58793f3c4683b1c3ec7.
Revert "Added new option '--list-subs' to show the available subtitle languages"

This reverts commit 2a4093eaf3af07fa0a74926ce09cb49aba73017e.
Revert "Added new option '--sub-format' to choose the format of the subtitles to downloade (defaut=srt)"

This reverts commit 9e62bc443996c1950de0841997c76d110cb77c6e.
Revert "Refactor subtitle options from srt to the more generic 'sub'."

This reverts commit 553d097442ad5ee62d227de2e2703a2377dcf40f.
Revert "Added new option '--all-srt' to download all the subtitles of a video."

This reverts commit ae608b8076497d70e2a95e5e939c1fb31e2dde53.
Finish reverting new and broken YouTube subtitle code:

Revert "Added new option '--only-srt' to download only the subtitles of a video"

This reverts commit cdb130b09a16865b81fd34d19b74fa634d45cad7.