[fpc-pascal] Type helpers now require an explicit modeswitch

[Sven Barth]

Hello together!

A little follow up of the feature announcement: After an internal 
discussion regarding language clarity last October it was decided that 
type helpers should not be enabled by default. Thus a new modeswitch 
"typehelpers" was added in revision 26796 that switches on "type helper 
for PrimitiveType" (non-Delphi modes) and "record helper for 
PrimitiveType" (Delphi modes).

Consequentially the same should be done for class and record helpers, 
but since they already had one mayor release cycle that's not that easy 
anymore (technically it is easy of course ^^).

Regards,
Sven