proposed changes for Terms and Definitions
update some execution details for PHP engine
Fixed broken link
Wrong variable name in the description
Small grammar fix
Fixing byRef assignment example consistancy

All other examples of byRef assignments use `$b =& $c`, while this one here used `$b = &$c`. Using the same syntax everywhere is just clearer.
Fixing simple typo
Fixing simple typo
Fixed occurrence of NULL that was outside of back-ticks.
Fixed incorrectly placed back-tick, causing the sigil to fall outside the formatted code.
Corrected to cover closure binding and scoping properly
Missing backticks
Merge branch 'pull-request/34'
Merge branch 'pull-request/35'
Merge branch 'pull-request/37'
Merge branch 'pull-request/39'
Merge branch 'pull-request/40'
Merge branch 'pull-request/41'
Merge branch 'pull-request/42'
Merge branch 'pull-request/44'