XXX: added scatter/gather APIs
XXX: removed types
XXX: removed compression
XXX: simplify retry logic in eblob_stress
mobjects: lock backend during eblob_remove_blobs()
tests: stress: test three read paths
tests: stress: test three stage write
blob: replace linux-only EBADFD with EILSEQ
blob: added __attribute_always_inline__ helper
blob: renamed eblob_update_index() to eblob_commit_disk()

Now it's consistient with eblob_commit_ram()
blob: allways update data and index file simultaniously.

This fixes bug when datafile index is not updated during overwrite.

Also removed cfg.bsize handling for now.