Replaced Open3 with Posix-spawn to reduce more process memory usage

Author: santhanakarthikeyan

README.md

@@ -49,10 +49,17 @@ hg 1.1.2
 If you are using CVS instead of CVSNT, you can potentially try creating
 a shell alias or symlink mapping 'cvsnt' to 'cvs'.
 
+Ohloh SCM uses [posix-spawn](https://github.com/rtomayko/posix-spawn) to
+execute commands so ensure *posix-spawn* gem is installed
+
+``gem install posix-spawn``
+
+
 ## Usage with Bundler
 
 ```
 gem 'ohloh_scm', git: 'https://github.com/blackducksw/ohloh_scm/', require: 'scm'
+gem 'posix-spawn'
 ```
 ## Running
 

lib/ohloh_scm/shellout.rb

@@ -1,6 +1,6 @@
 require 'rubygems'
 require 'stringio'
-require 'open3'
+require 'posix/spawn'
 
 class Shellout
 
@@ -9,9 +9,9 @@ def self.relay src, dst
   end 
 
   def self.execute(cmd)
-    out, err, exit_status = Open3.capture3(cmd)
+    posix_spawn = POSIX::Spawn::Child.new(cmd)
 
-    return exit_status, out, err
+    return posix_spawn.status, posix_spawn.out, posix_spawn.err
   end
 
   def run(cmd)