[Community] rtree not loading correctly

[Brian Burke]

Recap: I was having problems importing rtree because it was compiled 
under 64-bit and the libspatialindex.dll file was 32-bit.

I loaded the 64-bit version of libspatialindex that Howard compiled.  
Other than an error about a file named msvcp100.dll (which I don't think 
was related to my rtree issue and was resolved by installing this file), 
the new version ran great. Thanks for your help!!
-Brian