Add some more clippy ignores

Author: crsaracco

.travis.yml

@@ -14,7 +14,7 @@ jobs:
         - cargo build --verbose
         - cargo test --verbose
         - cargo fmt --all -- --check
-        - cargo +stable clippy --all-targets --all-features -- -D warnings -A clippy::unreadable_literal -A clippy::needless_range_loop -A clippy::float_cmp
+        - cargo +stable clippy --all-targets --all-features -- -D warnings -A clippy::unreadable_literal -A clippy::needless_range_loop -A clippy::float_cmp -A clippy::comparison-chain -A clippy::needless-doctest-main -A clippy::missing-safety-doc
     - stage: test
       os: osx
       before_script:
@@ -25,7 +25,7 @@ jobs:
         - cargo build --verbose
         - cargo test --verbose
         - cargo fmt --all -- --check
-        - cargo +stable clippy --all-targets --all-features -- -D warnings -A clippy::unreadable_literal -A clippy::needless_range_loop -A clippy::float_cmp
+        - cargo +stable clippy --all-targets --all-features -- -D warnings -A clippy::unreadable_literal -A clippy::needless_range_loop -A clippy::float_cmp -A clippy::comparison-chain -A clippy::needless-doctest-main -A clippy::missing-safety-doc
 
     # deploy crates and documentation conditionally
     # deploy on cargo if tagged master release