If `decodeURIComponent` error happen, just return the original value.

We need to catch decodeURIComponent() error, otherise it easy to make attack
request by `GET http://hostname/foo-category/100%`.
3.1.3
fix sample code
Merge pull request #65 from mzyy94/fix_wrong_code_in_readme

Fix sample code in README.md
Update koa-compose dependency.
3.1.4
Improve multiple routers example. Closes #68.
Expose route via `ctx.route`.
3.2.0
Update dependencies.
Disable Travis CI email notifications.
3.2.1