rgeos update breaks geojsonio install

[MicheleTobias]

Problem: the rgeos package updated this morning. geojsonio depends on regeos and is subsequently unable to see the install of regeos even when it is installed explicitly.

Solution: specify loading of version 0.5-8

[MicheleTobias]

After installing yesterday's version of rgeos, the problem is still not fixed. It might be an issue with geojsonio needing to update to reflect the changes in rgeos.

Proposed solution: wait a day or two to see if it gets fixed.