Add note for g2o_incremental
CommandArgs: output of vector<double>
include more file in the library

the library build in the calibration example now includes all classes
that are contained inside this folder.
setenv() does not exist on MSVC
Add initializer which uses the odometry
Integrate different initializer methods in g2o_viewer

The viewer now has a commbobox which allows to select different
initializer. Currently we have the former default spanning tree and
along odometry edges.
Odometry edges are detected by looking at the IDs of the nodes.
update README
Merge pull request #1 from RainerKuemmerle/master

update