#1132 writeHTMLCell warning when there are more than one <a> tags

[Matvey]

Hello. Just found what seems to be a little bug. I understand that the version of TCPDF I have is going to be deprecated.

Steps to reproduce:
(see attached file)
1) prepare an HTML string with more than one text, href values surronded by double quotes
2) pass this string to writeHTMLCell.

Result:
Warning: Illegal string offset 'url' in /path/to/tcpdf.php on line 18808
The amount of warnings is the amount of links with double quotes minus one.
As a consequence, TCPDF generates error due to some headers have been sent.

Having only one link, the string displays fine. Tried changing double quotes to single quotes (just in case). This removes warnings but produces unclickable links (blue, underlined, but not having hover and not taking us anywhere on click — as if hrefs were ignored).

Environment
TCPDF version: 6.2.9
OS: Windows 7
PHP: 7.1.2

This ticket is somewhat related: https://sourceforge.net/p/tcpdf/bugs/563/

[Matvey]

Also reproduces on
TCPDF version: 6.2.9
OS: FreeBSD
PHP: 7.0.9