Fix formatting typo in license.

Signed-off-by: Evan Nemerson <evan@coeus-group.com>
Rename tree-related structs to match coding style of other structs.

Signed-off-by: Evan Nemerson <evan@coeus-group.com>
plugins: Assign callbacks individually

If we do it this way we can add members to the SquashCodecFuncs struct
in the future if we need to.  Since this isn't a performance-critical
section of the code, I think it's worth it.

Signed-off-by: Evan Nemerson <evan@coeus-group.com>
Add LZF plugin.

https://github.com/quixdb/squash/issues/10

Signed-off-by: Evan Nemerson <evan@coeus-group.com>
plugins: Remove unnecessary plugin headers.

Signed-off-by: Evan Nemerson <evan@coeus-group.com>