Added appendTo() function to imitate '>>' redirect-and-append pipe.

[a10y]

@arturadib updated to your newer version. Passes tests on my machine (MBP OSX 10.8.4 node v0.10.8) hopefully will pass on travis as well!

[arturadib]

Looks good. I had screwed up the Travis config, let me merge and see what happens :) Thanks!

[arturadib]

Hi there, really sorry Andrew, but I overlooked some issues and decided to revert the patch. Can you please reopen the PR addressing these issues:

• Rename the function to .toEnd(), so that it's nicely grouped with .to() in the dir list (I know, I know, I'm sorry, I can be anal about naming :) Last time, I promise)
• Update the in-source docs in src/toEnd.js, and run scripts/generate-docs.js which will update README.md for you
• Create an explicit test showing that it creates a file if it does not exist (first test to confirm it doesn't exist, then show it exists with the right content)

Really appreciate your contribution, many thanks!

[a10y]

No need to apologize, I should have made it more compliant to start with :)
I'll send in the updated PR now.