G2o parsing code incorrectly names a variable as covariance instead of info matrix.

[tonioteran]

G2o file format uses the information matrix (e.g., for SLAM 2D https://github.com/RainerKuemmerle/g2o/wiki/File-Format-SLAM-2D).

In the utils here, the info matrix is incorrectly named TranCov:

SE-Sync/C++/SE-Sync/src/SESync_utils.cpp

Line 69 in 546f99b

Eigen::Matrix<Scalar, 2, 2> TranCov;

which, when creating for example tau, makes it read as tau = d / tr(cov^-1), when actually we want tau = d / tr(cov).

[tonioteran]

Excellent, no more confusion now (: