Pass the arguments during the slave method delegation

Also, rename the method to delegate_and_call_slave_method as it express
the meaning more cleanly.
Test the slave method caching
Add colors cache FAQ and fix typos
Bump the default chunk length to 49152
Don't bother with old IE support

I haven't actually tested it with old IE's anyway, no need to even try
to support those, unless someone complains.

Let's try to move the web forward and not live with all the burden old
browsers left us.
Build docker from rails/web-console
Update homepage in the gemspec
Refactor console_sessions.js asset
Add Monokai colors
Add v0.4.0 documentation section

The monokai theme is only available in master now. It is documented, so
let's not create the impression that its available in 0.4.0 as well.
Add the forgotten monokai colors file
Explain the color changing issues
Show travis badge for rais/web-console
Define WebConsoleTest and SlaveTest in WebConsole ns
Rename web_console_test to engine_test
Don't use refute

We kept this around so I can run the test suite on Rails 3 without
having to manually merge it for web-console-rails3. We are moving away
from that, and we're gonna alias refute in the test helper for
web-console-rails3.
Get coverage diagnostics during tests runs

Use the simplecov gem to get the results. They usually live under the
coverage/ directory, which I currently don't keep under version control.

Maybe it can be a good idea to keep it public. @guilleiguaran may want
to chime in with an opinion for that.
Test WebConsole::ConsoleSessionsController#configuration
Test WebConsole::Slave#dispose{,!} Errno::ESRCH reraise
Test WebConsole::Slave#pending_output errors