Dependency update, Clippy fixes, example/README updates, and formatting

[unv-annihilator]

Log and Hex dependencies updated:

• Upgraded log from version 0.3.8 to 0.4.1:
  • no code changes required
• Upgraded hex from version 0.2 to 0.3.1:
  • Updated client.rs from use hex::ToHex; to new use hex::encode as hex_encode;
  • Updated client.rs old to_hex() to use hex_encode()

Clippy added as optional feature for development:

• Added clippy as optional dependency, called via cargo build --features "clippy"
• Enabled clippy in lib.rs

Clippy Lint Fixes:

• Removed needless returns
• Removed needless pass-by-value
  • Update examples\src\main.rs to use &str instead of String
• Resolved possible lossy casting from u32 to u64
• Removed useless formats
• Changed unwrap_or followed by function into unwrap_or_else to resolve or_fun_call lint

README.md:

• Updated rust code in README.md to match latest changes to library
• Resolved multiple top level headers.
• Removed trailing spaces in rust examples.
• Add blankline below every header.
• Resolved bare url in README.md
• Add Websockets KLINE example to README.md

Example Code:

• Last changes to examples\src\main.rs to better match README.md changes made
• Bumped example binance-app version to 0.2.0

Formatted with rustfmt-nightly v0.3.4 Linted with Clippy v0.0.179

[wisespace-io]

Very good. Thank you for the contribution.