improved a few rake tasks

Rakefile

@@ -4,18 +4,26 @@ CLEAN << FileList["*.gem"]
 CLEAN << FileList["doc/*"]
 CLEAN << ".yardoc"
 
+$version = File.read("VERSION").chomp
+
+desc "run yardoc"
 task :doc do
 	sh "yard"
 end
 
+desc "run tests"
 task :test do
 	sh "rspec #{FileList["test/*.rb"]}"
 end
 
-task :package => :doc do
+task :gem do
 	sh "gem build spire_io.gemspec"
 end
 
+desc "generate docs and build a gem"
+task :package => [:doc, :gem]
+
+desc "build and install the gem"
 task :install => :package do
-	sh "gem install spire_io-*.gem"
+	sh "gem install spire_io-#{$version}.gem"
 end