Use boost's ptree to parse templight xml

<mdb-stdin> has to be renamed, since templight doesn't
escape file names, and rapidxml chocked on the angle brackets

This improves speed, but has a bad hit in the memory usage
since rapidxml pulls the whole xml into the memory.

Either way, speed has to be further improved.
Emphasize frame number in bt output
Add cmake option to compile for profiling
Handle exceptions locally in mdb_shell

Fixes #19
Rename mdb Command reference section in README.md

So people don't get confused when scrolling through the readme

Fixes #18
Upgrade to Boost 1.56.0 and redistribute (and build) the Boost source code with Metashell