add some more rdocs

lib/middleman/cache.rb

@@ -1,29 +1,51 @@
 module Middleman
+  # Simple shared cache implementation
   class Cache
+    
+    # Initialize
     def initialize
-      @cache = {}
+      self.clear
     end
 
+    # Either get the cached key or save the contents of the block
+    #
+    # @param Anything Hash can use as a key
+    # @return Cached value
     def fetch(*key)
       @cache[key] ||= yield
     end
     
+    # Whether the key is in the cache
+    # 
+    # @param Anything Hash can use as a key
+    # @return [Boolean]
     def has_key?(key)
       @cache.has_key?(key)
     end
     
+    # Get a specific key
+    #
+    # @param Anything Hash can use as a key
+    # @return Cached value
     def get(key)
       @cache[key]
     end
     
+    # Clear the entire cache
     def clear
       @cache = {}
     end
     
+    # Set a specific key
+    #
+    # @param Anything Hash can use as a key
+    # @param Cached value
     def set(key, value)
       @cache[key] = value
     end
     
+    # Remove a specific key
+    # @param Anything Hash can use as a key
     def remove(*key)
       @cache.delete(key) if @cache.has_key?(key)
     end

lib/middleman/core_extensions/extensions.rb

@@ -28,6 +28,9 @@
 # methods to use in your views. Some modify the output on-the-fly. And some
 # apply computationally-intensive changes to your final build files.
 
+# Using for version parsing
+require "rubygems"
+
 module Middleman::CoreExtensions::Extensions
   
   class << self

lib/middleman/version.rb

@@ -1,3 +1,6 @@
+# Using for version parsing
+require "rubygems"
+
 module Middleman
   VERSION = "3.0.0.alpha.3"
   GEM_VERSION = ::Gem::Version.create(VERSION)