in utils.download(), renamed the 'xml' option to 'binary'
the senate committee meetings parser should be downloading XML with the binary flag set to true, and with the next commit *must* because it cannot take unicode instances
Keep non-binary downloaded content in unicode

When downloading non-binary files, scrapelib/requests automatically does character-set detection,
but we've been ignoring it and using the raw bytes. It's probably incorrect to pass raw bytes
to JSON output, and it started causing errors creating XML output (lxml complained about
non-XML-compatible characters). Instead, we should always work in unicode when dealing with text.

This fix changes utils.download() to return unicode instances rather than str instances when
'binary' is not set to True.

Files cached to disk are now stored on disk in UTF-8 always, because when we load up cached
files we no longer know the character set that scrapelib/requests detected. Unfortunately
this means that some cache files may be invalid (just in cases where the original URL
returned non-UTF8 (probably ISO8859-1) content with actual non-UTF8 characters, which
seems to not be entirely common). Best to just clear your cache directory.

The scraper has always worked in bytes. download() was originally written to get the
text content using str(response), which was implicitly encoding the unicode response
back to bytes using the ASCII encoding, which can fail. In a1da46b78fc5c52881016109e53d664d8e51afd6
I fixed that by getting the text content using response.bytes directly, but I wish
I had just made it 'response' alone, which gives the unicode content.

Reverts 11a504cedc53c489809f083b35fba26b41a69b94 (recent work-around for char set issue)

Fixes #82
house committee meeting parser tweaks

Don't bother saving meeting info for meetings more than 60 days ago.

Don't skip a meeting if a subcommittee isn't recognized, just ignore the subcommittee.
I broke VP tie-breaker votes

In cebffaeb051e2fc694ee8f70c8cacab7e4caf748 I forgot to test if the voter ID is the string "VP"
when reading from the cache directory, look for .zip files containing cached directories and load cached files from the .zip if they exist