Refactors bench HTTP request generation to ease testing in preparation for changing auth header handling
Updates bench to pass user-specified authentication header directly
Adds bench tests for eventToRequest method
Moves constants inside the only func that uses them in bench_test (and adds newline at EOF)
benchAuthParam -> authParam in bench_test
Merge pull request #2 from Clever/INFRA-111-convert-logs-to-gobench-input

Updates bench to pass through given authentication header as is