10 chain saw manuals added

 Links to 10 more chain saw manuals have been added:

- Homelite: 1 chain saw manual
- Husqvarna: 1 chain saw manual
- Skil: 2 chain saw manuals
- Stihl: 3 chain saw manuals, 1 chain saw service manual, 1 chain saw parts list
- Yardworks: 1 chain saw manual

Skil chain saw manuals

Instruction manuals:
- Skil Skilsaw 0780 (F0150780) Chain Saw (Apr 2011)

- Skil Skilsaw 0780 (F0150780) Chain Saw (Apr 2017)

- Skil Skilsaw 1614 / 1616 Type 1 Gasoline Chain Saw (1976)