Add '?' suffix to generated method names of bools

Objects with values that are either true or false have an '?' appended to
their name to fit with standard Ruby convention. For example, Repository
objects now have a .fork? and .private? method. This convention is not
reflected in the value of the @keys instance variable, because we assume
callers will use it to iterate through the instance variables, whose names do
not have a '?' suffix...

Note: This commit theoretically breaks backward compatibility, as the
unadorned method names no longer work.

This closes fcoury#2.

lib/octopi/base.rb

@@ -40,11 +40,13 @@ def initialize(api, hash)
         next if k =~ /\./
         instance_variable_set("@#{k}", v)
 
-        self.class.send :define_method, "#{k}=" do |v|
+        method = (TrueClass === v || FalseClass === v) ? "#{k}?" : k
+
+        self.class.send :define_method, "#{method}=" do |v|
           instance_variable_set("@#{k}", v)
         end
 
-        self.class.send :define_method, k do
+        self.class.send :define_method, method do
           instance_variable_get("@#{k}")
         end
       end