updating docs, and added --private flag to .yardopts to include private methods in documentation

.yardopts

@@ -1 +1 @@
---markup markdown
+--markup markdown --private

README.markdown

@@ -354,7 +354,7 @@ A valid Pry command object must inherit from
 #### Example: Defining a command object and setting it globally
 
     class MyCommands < Pry::CommandBase
-      command greet", "Greet the user." do |name|
+      command "greet", "Greet the user." do |name|
         output.puts "Hello #{name.capitalize}, how are you?"
       end
     end

lib/pry/prompts.rb

@@ -1,6 +1,6 @@
 class Pry
 
-  # The default prompt; includes the target
+  # The default prompt; includes the target and nesting level
   DEFAULT_PROMPT = [
                     proc do |target_self, nest_level|
                       if nest_level == 0

lib/pry/pry_instance.rb

@@ -192,10 +192,8 @@ class Pry
       action = data[:action]
       
       options = {
-        :captures => args_string,
-        :eval_string => eval_string,
-        :target => target,
         :val => val,
+        :eval_string => eval_string,
         :nesting => nesting,
         :output => output,
         :commands => commands.commands
@@ -211,9 +209,6 @@ class Pry
       case action.arity <=> 0
       when -1
 
-        # if arity is negative then we have a *args in 1.8.7.
-        # In 1.9 we have default values or *args
-        # Use instance_exec() to make the opts, target, output, etc methods available
         commands.instance_exec(*args, &action)
       when 1, 0
 
@@ -223,8 +218,7 @@ class Pry
         # doesn't care)
         args_with_corrected_arity = args.values_at *0..(action.arity - 1)
 
-        # Use instance_exec() to make the opts, target, output, etc methods
-        # available        
+        # Use instance_exec() to make the `opts` method, etc available
         commands.instance_exec(*args_with_corrected_arity, &action)
       end