Fix packaging script to build user custom package:
* separate td command and td-agent-ui from td-agent-files
* move package-scripts from files to template
  * and rewrite them with install_path and package names
  * to generate scripts w/ package names and install path
* do refactoring td-agent-files
  * path generation
  * writing results of template engines

Squashed commit of the following:

commit 90db4967ff7016d744343dd906a4b7eedb5c7854
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Sat Dec 6 01:02:19 2014 +0900

    fix bug of conf path

commit d1cff106f498d230dc419fb18db227d01a877beb
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 23:01:40 2014 +0900

    fix buggy path

commit 33819f577e4d5a2c360cc3bc1f24e4f975752a63
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 20:30:15 2014 +0900

    fix bug for default configuration directories

commit c4df90f4583a5d0c7ad0f8036efc1019c3b46f0e
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 20:23:44 2014 +0900

    add Gemfile.lock not to add this file

commit 9c66ca1d45027e3849a77d2c99b68b2d0d61a837
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 20:23:19 2014 +0900

    fix to use template.call() to simplify path generation

commit c450d73c8b24825a661903d282ab92794ed72fa0
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 19:17:11 2014 +0900

    fix syntax bug

commit 0d219c748bb35ae0683b61dba1f558d79a317b65
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 18:04:04 2014 +0900

    Separate td/td-agent-ui (optional software) into different software
     * to be able to control include them or not by project configuration

commit 246e770955d77265c14d66e8d30ac62ee29c1b96
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 17:29:56 2014 +0900

    fix buggy path name

commit 42e8dbf9eac3d4d5a46e2f75ad0b29a5b76ff71e
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 17:28:06 2014 +0900

    fix to prepare parent directory for actual generated path

commit aead5fc7a3460ddeea69e899c08c9860496fbdda
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 17:23:46 2014 +0900

    fix typo

commit 327747156df37d1c0618145282de76414b358a4c
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 17:21:36 2014 +0900

    fix bug to specify template path name

commit b7e3b529f766cce2094470d012af0512ee6c7818
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Fri Dec 5 17:18:26 2014 +0900

    fix not to use "def": omnibus evaluates code in their special context

commit e607105ac5e2e36cf71908f7b8012a5229886880
Author: TAGOMORI Satoshi <tagomoris@gmail.com>
Date:   Thu Dec 4 19:23:17 2014 +0900

    fix to be able to change project name
add how to build users own package
fix build steps to reduce conflict against updates
Merge pull request #12 from tagomoris/build-own-package

Build packages with customized plugins, configurations and package name