[fpc-pascal] Download EmbWeb sources

[Marco van de Voort]

In our previous episode, Lee Jenkins said:
> M:\lazarus_current\lazarus\fpc\2.5.1\bin\i386-win32>fppkg install embweb
> The FPC Package tool encountered the following error:
> [embweb] Package fcl-web <none> is not available
> 
> M:\lazarus_current\lazarus\fpc\2.5.1\bin\i386-win32>fppkg list
> Name                 Installed        Available
> embweb               -                0.9.0-926
> gecko                -                0.9.0-1504
> jquery               -                0.9.0-842
> lazmkunit            -                0.9.2-1
> lnet                 -                0.6.4-2534
> webdesign            -                0.9.0-906

Looks like snapshot generation is not yet adapted to the fppkg model.