[Lazarus] Replacing Delphi function calls with FCL/LCL functions by converter

[Juha Manninen]

> shellexecute isn't only used for urls. Do you chekc if the third argument
> starts with http:// or so?

I could extend the syntax to do that. I will also add the comments later.

Fully automatic conversion is not realistic. The person has to go through the 
code manually anyway, so 100% accuracy is not required here.

Juha