Recent ConTeXt versions have breaking changes

[paolobrasolin]

• \meaning\somemacro is now macro:... instead of macro:->...
  • breaks katharizo implementation (which uses matches on the arrow in a macro definition)
  • breaks koinos tests implementation
• \meaning" is now the character U+0022 'quotation mark' instead of the character "
  • breaks velos implementation (which uses /handlers/first char syntax)
• \meaning\space is now blank space character U+0020 'space' instead of blank space
  • breaks koinos tests implementation
• error message for undefined macros has changed
  • breaks ektropi tests implementation