Correcting typo in writing.rst

Simple typo: "fishes" -> "finishes"
Merge pull request #205 from duailibe/patch-2

Correcting typo in writing.rst
Adding "keep new files" option to convert plugin
Changing behavior in "keep new files"
Merge pull request #209 from duailibe/convert

Adding functionality to convert plugin: keep newly converted files
changelog/cleanup/fixes for #209

The major functional change here is how files move around when in keep_new
mode. Now, files are first moved to the destination directory and then
copied/transcoded back into the library.

This avoids problems where naming conflicts could occur when transcoding from
MP3 to MP3 (and thus not changing the filename).
convert: read new audio metadata (#208)