upload_file_stream now returns file_name with the original name.
create_flash_task accepts { file, name } so a streamed path can
keep the real filename on the fileset.
Fixes#361
create_flash_task already accepted `name`, but the flash card still
showed the first filename. Use a non-empty name as the fileset title
and keep the real filenames on the files themselves.
Fixes#363
create_flash_task loaded every fileset file through loadBinarySource
and kept the bytes through hash, commit, and sliceupload, so a single
file over 1 GiB could not be sent. Stage to disk like group files,
stream MD5/SHA1/Sha1StateV, then POST 1 MiB chunks from FileChunkSource.
Do not reuse video sha1Blocks as Sha1StateV: an exact N-MiB file would
ship an extra un-finalized last-slice state. Local/HTTP sources use the
4 GiB group-file ceiling; inline base64 stays at 1 GiB because stage
still decodes it in RAM. Protocol order, seconds-pass, and multi-file
commit are unchanged.
Fixes#359
DrSmoothl