Fixing lots of remaining spacing and formatting issues.
Miscellaneous improvements:

* Simplifying logic in minJ_BC
* Refactor readmetr to use ifstream
* Use default op=
* Fixing some numerical constants.
* Making some parameters non-const and adding accessors.
* Add error checking for fopen.
* Passing std::strings instead of char*
* Fixing up the metr_data_gen() function.
* Properly initialize _dist_norm.
Converting metr_data_gen to iostreams.