Revert "parser: experimentally set preservewhitespace to false"

This reverts commit b69d94eeeb6ed539267a4328265354a45d23ba86.
parser: trim some some feed-extracted data link titles and links
public: remove subscribe2 (unused?)
split functions php into two parts because syntastic is too slow
get_feeds_from_html: stricter feed detection based on whatwg guidelines
comment out subtest
sanity_check: ERRORS was not imported from global scope
get_feeds_from_html: add rel='alternate feed'
Revert "get_feeds_from_html: add rel='alternate feed'"

This reverts commit 526e1d80be3fe843798c4e26964e10e25a48ae7a.