Reduce dependencies

[algesten]

I've made a version of h2 that is "tokio free". Then I proceeded to analyze my dependencies in depth. I specifically am hunting dependencies that are pulled in by one single crate and nothing else. Some crates like h2 and async-trait, I'm accepting and not listing.

async-comp              adler32 v1.0.4
async-comp              crc32fast v1.2.0
async-comp, cookie      libc v0.2.70
async-comp, fut-util    memchr v2.3.3
cookie                  proc-macro-hack v0.5.15
cookie                  rustversion v1.0.2
cookie                  standback v0.2.8
cookie                  time v0.2.9
cookie                  time-macros v0.1.0
cookie                  time-macros-impl v0.1.1
fut-util                pin-project v0.4.17
fut-util                pin-project-internal v0.4.17
fut-util                pin-utils v0.1.0
fut-util                proc-macro-nested v0.1.4
futures-util            futures-macro v0.3.5
futures-util            futures-task v0.3.5
public-suff             error-chain v0.12.2
public-suff             idna v0.2.0
public-suff             lazy_static v1.4.0
public-suff             matches v0.1.8
public-suff             regex v1.3.7
public-suff             regex-syntax v0.6.17
public-suff             smallvec v1.4.0
public-suff             unicode-bidi v0.3.4
public-suff             unicode-normalization v0.1.12
public-suff             version_check v0.9.1
serde_json              ryu v1.0.4

In terms of figuring out alternatives the contenders are:

1. public-suffix
2. async-compression
3. cookie
4. futures_util

[rushmorem]

https://github.com/algesten/hreq/pull/36 eliminated publicsuffix.