Add armadillo package (#2193)

* Add armadillo package

* Fix armadillo package.

packages/armadillo.rb

+require 'package'
+
+class Armadillo < Package
+  description 'Armadillo is a high quality linear algebra library (matrix maths) for the C++ language, aiming towards a good balance between speed and ease of use'
+  homepage 'http://arma.sourceforge.net/'
+  version '8.400.0'
+
+  source_url 'https://downloads.sourceforge.net/project/arma/armadillo-8.400.0.tar.xz'
+  source_sha256 '5cb6bc2f457a9d6a0758cfb15c418d48289909daccd79d0e428452029285dd9b'
+
+  depends_on 'openblas'
+
+  def self.build
+    system "./configure",
+           "--prefix=#{CREW_PREFIX}",
+           "--libdir=#{CREW_LIB_PREFIX}"
+    system "make"
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+
+end