Port Dopri/Radau from numarray to numpy

This commit fixes #24
Revert skipping Radau/Dopri tests when numpy>1.8

This reverts commit f1380415f79194ecd1f15bb542a57cf60a04a864.
Update repo docs
Fix memory leak (resolves #69)
Merge pull request #68 from z2v/bug/24-port-to-libnumpy

Porting Dopri/Radau to libnumpy
Merge pull request #71 from z2v/bug/69-memory-leak

Fix memory leak (resolves #69)