Reduce the number of keywords in Cargo.toml to 5 - the maximum supported by crates.io
Reduce the number of keywords in Cargo.toml to 5 - the maximum supported by crates.io

nmathewson/rust-crypto,thinkingfish/rust-crypto,mseri/rust-crypto,andreasots/rust-crypto,canndrew/rust-crypto,canndrew/rust-crypto,tempbottle/rust-crypto,tempbottle/rust-crypto,DaGenix/rust-crypto,andreasots/rust-crypto,vladikoff/rust-crypto,PeterReid/rust-crypto,nmathewson/rust-crypto,DaGenix/rust-crypto,thinkingfish/rust-crypto,mseri/rust-crypto,PeterReid/rust-crypto,exe-dealer/rust-md5