[SVN r53753]
the following tickets: #1622 (r50206), #2550 (r50191), #416 (r50137), #2460 (r49563), #2392 (r49254), #2209 (r49000), #1700 (r48611). Also adds metric_tsp_approx algorithm. [SVN r50330]
documentation and tests. Integrated the test into the unit tests, and the documentation into the TOC under a new subsection named Paths and Tours. Also added a new bad_graph exception in exception.hpp. [SVN r49561]