v0.3

Added:
XML output #27
DNS prefetch option #17

Improved:
Test coverage #11 #13
Verbose and quiet behavior #16
Library documentation #14

Breaking changes:
Default config file is pewpew.{json,toml} instead of config.{json,toml}
Count and Concurrency are now properties of StressConfig, not Target.
CreateTextSummary was renamed to CreateTextStressSummary