Use Travis cache.

[skip ci]
Merge pull request #987 from methane/travis-cache

Use Travis cache.
Update the Perl Kelp framework

Added additional test routes according to the requirements at
http://www.techempower.com/benchmarks/#section=code
Update README.md for Perl Kelp

Added more information on how to deploy a Perl Kelp application via
uWSGI and Plack, as well as the CPAN modules to install.
Indicate that kelp using nginx
Remove kelp dependency on running code from ~/FrameworkBenchmarks
Update nginx user for kelp