Merge pull request #4897 from ethereum/trailingWhitespaceDetection

Trailing whitespace detection script and circleci job.

scripts/detect_trailing_whitespace.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+REPO_ROOT="$(dirname "$0")"/..
+
+(
+cd $REPO_ROOT
+WHITESPACE=$(git grep -n -I -E "^.*[[:space:]]+$" | grep -v "test/libsolidity/ASTJSON\|test/compilationTests/zeppelin/LICENSE")
+
+if [[ "$WHITESPACE" != "" ]]
+then
+	echo "Error: Trailing whitespace found:" >&2
+	echo "$WHITESPACE" >&2
+	exit 1
+fi
+)