dead README links

[KonradHoeffner]

The following deb package download links are dead:

• Via the Linked Data Stack (recommended)
• Download from the Sparqlify website's download section.

[Aklakan]

Oh my, its really time to update the README; despite a bit of bitrod it is otherwise still functional - and with the work on SANSA it is even likely it will receive a few updates

[ajflash]

The second link mentioned in the readme is also broken: "Support of the 'Sparqlification Mapping Language' (SML)"