CC BY-SA 4.0 for GPL compat

new function trim_leading_urls

new function from Falcon, trim_leading_urls, useful for generating post
name/title from plain text that is usually auto-linked/embedded, e.g.
photo posts

Merge pull request #11 from pfefferle/master

added a "loader" to be more composer friendly. thanks @pfefferle!

substr() neg offsets, new ctype_email_local(), auto_link() avoid link…

…ing email domain as handle

fix substr() neg offsets.
add new function ctype_email_local() with minimal good enough
implementation.
a few whitespace tweaks.
fix auto_link() to avoid linking email address domain name as Twitter
handle.

fix commenting in PHP-only block

add number(), y_to_days, fix ymd_to_days, simplify yd_to_days

add number() and y_to_days functions. fix ymd_to_days to use yd_to_days
(previously had a JS-only problem on DST boundaries), and fix
yd_to_days to use y_to_days simpler flow.