Important note about "experimental" branch
==========================================

Goal of the "experimental" branch is to merge all the stuff:
- changesets from master branch
- features that DO IMPACT compatibility
- play with new technologies
- etc.

THERE IS NO GUARANTEE THAT IT IS COMPATIBLE WITH MASTER BRANCH OR PREVIOUS
"experimental" CODE nor THAT YOU CAN SWITCH BACK AND FORTH BETWEEN BRANCHES
WITHIN THE SAME REPOSITORY WITHOUT ENCOUNTERING SEVERE ISSUES.

Please also see the LICENSE for more informations.


Stuff in "experimental" that is not in "master" minus minor changes
===================================================================

added tuning docs

attic init --compression NN --cipher NN --mac NN ...
(see attic init --help)

new hashes:      sha512-256
                 sha512
                 sha1
                 ghash (default)
new MACs:        hmac-sha512-256
                 hmac-sha512
                 hmac-sha1
                 gmac (default)
new ciphers:     aes256-ctr + hmac-sha512-256
                 aes256-gcm (default)
new compression: no compression (default)
                 zlib level 1..9 (previously, level 6 was hardcoded)
                 lzma preset 0..9
                 lz4 (and other) multi-threaded algos from blosc library

source: more flexible type 0x03 header format, allowing to give hash algo,
compression algo and level, encryption algo, key type.

IV is stored in full length, length of stored IV/MAC/hash is flexible.
Indexing key size (key = id_hash()) is flexible and configurable per repo.

source: less hardcoding, numeric offsets / lengths
source: flexible hashing, compression, encryption, key dispatching