Change to mPDF library for HTML printing support
Fix last of lint issues leading up to packaging
Don't process alpha channel of PNG images
Use consistent styles for printed ticket thread
Merge branch 'develop' into feature/html-pdf
Use <pre> elements for text emails

This provides better compatibility with mPDF, which doesn't support the CSS
white-space:pre-wrap property
Complete lint testing for mPDF
Fix incorrect sql statement

in Client::getLastTicketIdByEmail()
Upgrade to Redactor 9.1.6
Merge pull request #46 from greezybacon/issue/bad-sql

Fix incorrect sql statement

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #47 from greezybacon/issue/redactor-916

Upgrade to Redactor 9.1.6

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #44 from greezybacon/feature/html-pdf

Support HTML printing  to PDF

Reviewed-By: Peter Rotich <peter@osticket.com>
Render empty tables as an empty string
Merge pull request #48 from greezybacon/issue/html2text-empty-tables

Render empty tables as an empty string

Reviewed-By: Peter Rotich <peter@osticket.com>