Indentation of partials according to spec

[dpoetzsch]

Hi,

I noticed that the following testcase of the mustache spec is not rendered correctly (the partial is not indented):

  - name: Standalone Indentation
    desc: Each line of the partial should be indented before rendering.
    data: { content: "<\n->" }
    template: |
      \
       {{>partial}}
      /
    partials:
      partial: |
        |
        {{{content}}}
        |
    expected: |
      \
       |
       <
      ->
       |
      /

The current outcome is:

\
 |
<
->
|

/

I am using mustache templating for markdown templates where whitespace does matter, so this is a real problem for me.

I saw that the readme states Passes all of the mustache specification tests modulo whitespace differences. Is this on purpose or would a PR that tries to fix this difference from the spec be welcome?