Incorrect footprints in Isolator.lib

[Ratfink]

As reported by @alaut at #520 (comment):

It appears to me that TLP291-4 and others in the Isolators.lib library are associated with the wrong footprints. I'm not nearly experienced enough to make any reliable attempt to correct through these yet... though I plan to contribute sooner than later.

For example. I'm not sure if technically the footprint associated with LTV-847S is correct or within a certain tolerance. Datasheet indicated 9mm width, footprint appears to be 9.53mm. I'm inclined to believe I'm wrong here.

TLP291-4 is definitely wrong though by a lot unless I'm missing something. According to the datasheet, the pitch is 1.27mm not 2.54 as associated in Package_DIP:SMDIP-16_W7.62mm

I agree that TLP291-4 is definitely wrong, and LTV-847S looks suspicious as well.

[evanshultz]

Fixed in #1177.