updated gemspec for skewheap

Signed-off-by: pjs <pjs@alum.mit.edu>

simplekit.gemspec

 # -*- ruby -*-
-_VERSION = "0.3.2"
+_VERSION = "0.4.0"
 
 Gem::Specification.new do |s|
   s.name = "simplekit"
   s.version = _VERSION
-  s.date = "2012-03-14"
+  s.date = "2013-01-14"
   s.summary = "Discrete event simulation engine."
   s.homepage = "git://or.nps.edu/simplekit-ruby.git"
   s.email = "pjs@alum.mit.edu"
@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
     lgpl.txt
     lib/simplekit.rb
   ]
-  s.add_runtime_dependency 'pqueue', '~> 2.0.2'
+  s.add_runtime_dependency 'skewheap', '~> 0.1.0'
   s.required_ruby_version = '>= 1.8.1'
   s.license = 'LGPL'
 end