New option: block-indent (#92)

[tonyganch]

Note: All pull requests will stay open for a week so everyone has some time to review and leave comments.

Set indent for code inside blocks, including media queries and nested rules (see #92).
This should also fix #163.

Example: { 'block-indent': 4 }

// Before:
a {
top: 0;
  p {
      color: tomato;
position: happy;
 }
}

// After:
a {
    top: 0;
    p {
        color: tomato;
        position: happy;
        }
    }

[tonyganch]

@chrisdhanaraj, have you deleted your comment?

To make this work you can use both block-indent and space-before-closing-brace.
For example: { 'block-indent': 4, 'space-before-closing-brace': '\n' }

// Before:
a {
top: 0;
  p {
      color: tomato;
position: happy;
 }
}

// After:
a {
    top: 0;
    p {
        color: tomato;
        position: happy;
    }
}

[chrisdhanaraj]

Hah yes, sorry! I realised that space-before-closing-brace option right after I posted my comment, I probably should've just edited it instead.