introduce basic blogger importer
add body replacement, liquid escape and internal link replacement
Remove the comments from the Importer::Blogger class, ref dddc8bcee5469bf3323f0a15eced9881ec915700
add options tags, leave-blogger-info, and replace-internal-link
blogger importer supports thumbnail now
blogger importer supports author and modified time now
fix blogger internal link replacement (--replace-internal-link option)
remove --tags option from blogger importer
fix blogger importer commandline options: --leave-blogger-info and --replace-internal-link
fix replace-internal-link not prepends base URL in blogger importer
fix blogger importer commandline options: --leave-blogger-info=>--no-blogger-info and --replace-internal-link
fix draft post issue on blogger importer
for blogger importer, add docs and fix how-to-use message in jekyll import blogger

Usage:

  jekyll import blogger [options]

Options:
            --source NAME  The XML file (blog-MM-DD-YYYY.xml) path to import
            --no-blogger-info  Leave blogger-URL info (id and old URL.) as YAML data (default: false)
            --replace-internal-link  Whether to replace internal links with the post_url liquid codes (default: false)
        -h, --help         Show this message
        -v, --version      Print the name and version
        -t, --trace        Show the full backtrace when an error occurs
remove a debug code for blogger importer
fix in test/test_blogger_importer.rb

Two 'the in-elem-entry-to-post-data converter should raise an error if original_url not exists.' exists (duplicated).
So the 2nd test is replaced with '...should raise an error if non-post-kind not exists'.
In addition, fix the 1st test.
In BloggerAtomStreamListener, use `extend` instead of `include` to use `require_deps` instead of `require`
Merge pull request #162 from cat-in-136/spike-blogger-support