add casperjs.gemspec for build gem.

+
+
+Gem::Specification.new do |s|
+  s.name                = "casperjs"
+  s.version             = "1.0.0.RC1"
+  s.homepage            = "http://casperjs.org/"
+  s.authors             = ["Nicolas Perriault", ]
+  s.email               = ["nperriault@gmail.com",]
+  s.description         = "CasperJS is a navigation scripting & testing utility for [PhantomJS](http://www.phantomjs.org/).
+It eases the process of defining a full navigation scenario and provides useful
+high-level functions, methods & syntaxic sugar for doing common tasks."
+  s.summary             = "Navigation scripting & testing utility for PhantomJS"
+  s.extra_rdoc_files    = ["LICENSE.md", "README.md"]
+  s.files               = Dir["LICENSE.md", "README.md", "CHANGELOG.md", "package.json", "casperjs.gemspec", 
+                            "bin/bootstrap.js", "bin/usage.txt", "bin/casperjs_python", 
+                            "docs/**/*", "modules/**/*", "samples/**/*", "tests/**/*"]
+  s.bindir              = "rubybin"
+  s.executables         = [ "casperjs" ]
+  s.license             = "MIT"
+  s.requirements        = [ "PhantomJS v1.5" ]
+end