Fix improper line indentation when no results are returned

[sorrell]

When no results are returned from an eval, the "prompt" text will be improperly indented. See below.

[ghost]

I see this happening even when there are results. The first output line is always indented, for example:

json> print /a
      1
json> print /
      Cannot evaluate JSON pointer "/" because the object at "" does not contain a property named "".
Parameter name: referenceToken
json> print /b
      [
  "x",
  "y"
]
json>
      json>
      json>

[ghost]

By the way, nice package, just what I was looking for!

[sorrell]

I'll see if I can take a look at this this weekend/soon. And thanks!