Error after merging pull request #148

[Sjonnie2nd]

On parsing one of my emails node crashes on mailParser.js line 1047:
} else if (this.mailData.text[i].content) {.
The error message: Cannot read property 'content' of undefined.
This seems to be caused by #148

When debugging:
i=1,
this.mailData.html.length=2
this.mailData.text.length=1.

Without digging too much in the surrounding code i fixed this with:
} else if (i < this.mailData.text.length && this.mailData.text[i].content) {

Am I right here?

[andris9]

Fix published as v0.6.1