Merge branch 'issue/23_ftp_2' into develop
body: Support passthrough __iter__()
ftp.ls: Fix up parsing Unix ls where 1 space between user and size.
ftp.client: Support fetch both NLST and LIST.
scraper.util.is_unlikely_link: Include \ and html tags.
scaper.javascript: Try JSON decode before is_unlikely_text
document.css,scraper.css: Reject links longer than 500 chars.
fuzz_fusil: Update fusil test cases to match URL warning

[ci skip]
cache.cacheItem: Compare key in total ordering to avoid false equals

Closes chfoo/wpull#191
changedlog: Add entry about CacheItem fix.

[ci skip]
Add --debug-manhole option for installing Manhole socket
scraper.util: Use warning string consistent with url module.

[ci skip]
scraper.javascript: Fix nonsensical link scraping code

Regression introduced in 342acf5368d0b2fc484b4cf3e5e44fb390b9ab4a and
made worse by 342acf5368d0b2fc484b4cf3e5e44fb390b9ab4a

Closes chfoo/wpull#192
string.format_size: Fix format error when sizes are terabytes.

Increase coverage.
Add unit test decompression.gzip_uncompress() for coverage.
document.util: Use function instead of duplicate code (coverage)
Add unit test for observer module (coverage)
travis.yml: Add coveralls config. readme: Add coveralls badge.
app_test: Handle Travis CI slowness on test scripting hooks
connection: Handle SSLErrors with "unknown ca".