Remove TSqlSelectString and related dependency

Fix vimeo#1628 - improve behaviour of unset in loops

Fix vimeo#1616 - allow Psalm to output checkstyle format

Allow MixedArrayTypeCoercion to be properly suppressed by default

Fix checks for parent method implementers

Add documentation for unused method/property removal/

Remove type coverage map, as it’s not ready for prime-time

Fix buggy behaviour around callable tests

loading in cacert.pem-related changes from psalm/shepherd@4b5b820 as …

…recommended by @muglug

Set better permissions on Travis deploy script