- Upgrade Eigen2 library to Eigen3
- Upgrade colamd library and placed in extern/ so other libraries from extern/ can use it
NOTE: With previous version of Eigen (3.0.1) it was necessary to define
EIGEN_DONT_ALIGN_STATICALLY macro to make it compilable on windows 32bit.
After latest upgrade it seems to be unnecessary (at least when was testing libmv),
so i removed that defines which can reduce speed and lead to other problems.