[parity-util-mem] migrate code to 2018 edition (#231)

* Update to 2018 edition for parity-util-mem

Signed-off-by: Saurav Sharma <appdroiddeveloper@gmail.com>

* update missing use statement

Signed-off-by: Saurav Sharma <appdroiddeveloper@gmail.com>

* add no_std to ci and use a rstd alias.

* Remove 2 files from parity-util-mem

Signed-off-by: Saurav Sharma <appdroiddeveloper@gmail.com>

Author: iamsauravsharma

.travis.yml

@@ -33,6 +33,7 @@ script:
   - cd parity-util-mem/ && cargo test --features=estimate-heapsize && cd ..
   - cd parity-util-mem/ && cargo test --features=jemalloc-global && cd ..
   - cd parity-util-mem/ && cargo test --features=mimalloc-global && cd ..
+  - cd parity-util-mem/ && cargo test --no-default-features --features=dlmalloc-global && cd ..
   - cd rlp/ && cargo test --no-default-features && cargo check --benches && cd ..
   - cd triehash/ && cargo check --benches && cd ..
   - if [ "$TRAVIS_OS_NAME" == "linux" ]; then

parity-util-mem/Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 repository = "https://github.com/paritytech/parity-common"
 description = "Collection of memory related utilities"
 license = "GPL-3.0"
+edition = "2018"
 
 [dependencies]
 cfg-if = "0.1.6"