Version 0.3.13 "Prepare for 0.4!"

Because our plan to the version 0.4 is finally ready, this release
makes our first steps for the next major release (most likely 0.4).

In fact, some changes are directly from ongoing version 0.4 design branch.

*   Deprecation of certain types, modules, traits and operator overloads.
*   New: `prelude` public module
    *   It's currently empty but `use ssdeep::prelude::*;`
        will be convenient on the next major release.
*   Other minor fixes / changes
    *   To keep MSRV low, tests need a *lower* version of the `libc` crate.

Author: a4lg

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "ffuzzy"
-version = "0.3.13-alpha.0"
+version = "0.3.13"
 description = "Library to generate / parse / compare ssdeep Context Triggered Piecewise Hashes (CTPH)"
 authors = ["Tsukasa OI", "Helmut Grohne", "Jesse Kornblum"]
 keywords = ["ssdeep", "fuzzy", "hash", "security", "clustering"]