chmhelp: added menu item to open all chm files, patch 23411

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40589 4005530d-fff6-0310-9dd1-cebe43e6787f
chmhelp: fixed crash when lhelp is not there and give a hint what to do

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40590 4005530d-fff6-0310-9dd1-cebe43e6787f