#380: shortcut/compatibility options

These config options make it easier to customize the command (no need to make
a single-element formats dict). And the opt config option provides backwards
compatibility with the previous style.
convert: fix outdated reference, col wrap
#380: Template.safe_substitute

This way, you almost never need to use the $$ escape sequence.
convert: extension is a bytestring (fix #390)
fix ihate docs example (fix #393)
mediafile: optionally save ID3v2.3 tags
PEP8ify mediafile.py
id3v23 config option (fix #388)
scrub: no need to save after delete()

The delete() method on Mutagen objects writes the file directly. Calling
save() was unnecessary and, in at least one case we found, could inadvertently
preserve non-standard tags that Mutagen did not understand.
API docs: slightly less skeletal
1.3.1: changelog summary & release date
Added tag v1.3.1 for changeset 78ce7bd4a1d1
typo
add missing ftintitle docs
version bump: 1.3.2
readme: fix plugin-writing link, add mailing list link
readme: more relevant plugin callouts
missing: tolerate disctotal == None

This problem:
http://pastebin.ca/2466454
is likely indicative of a bug elsewhere, but defensive coding seems like a
good idea here.
per_disc_numbering: fall back to global indices

If the per-medium values aren't available, use the global numbers.
Added min_weight option to lastgenre, to provide for filtering out unpopulare genres.