Standardise the indentation and line endings in the test suite

I've encountered the following different indentation styles in twig.js' test code:

* Two-space indentation
* Four-space indentation
* Eight-space indentation
* Tab indentation

There's also a mix of UNIX and DOS line-endings in one file. In some cases, the indentation varies *within a given line*. This has been making life unnecessarily difficult when attempting to add functionality and fix bugs. I keep having to perform awkward text editing operations such as replacing the first tab on each line with eight spaces.

These commits fix all the above, standardising on tabs and UNIX line-endings. I'm certainly not a "tabs zealot" or anything like that. I only chose them because I think I've encountered more tabs in this code than anything else. But if you'd rather it was something else, just say the word and I'll change it to that.