fix #184 sphere radius default to 0.5f
Merge pull request #186 from 2014-Android-ITX4/fix-184

fix #184 sphere radius default to 0.5f
fix #185 rotate camera by swiping
Merge pull request #187 from 2014-Android-ITX4/fix-185

fix #185 rotate camera by swiping
fix #190
Merge pull request #191 from 2014-Android-ITX4/fix-190

fix #190