README improvements.
Fix RDoc deprecation; allow tasks with Jeweler, but hint it.
"rake test" prepares $LOAD_PATH.
Prefer Pry for the console.
Improve test readability.
No need to use explicit self in a class method body; it is the default.
Double explicit return separated by if is hard to read.
Remove explicit return and self, improve naming.
To avoid echoing the command, use system.
Restore summarize documentation.