Multi index

I removed the old v1_40 folder and moved the printers one folder up. I added the version number to individual subprinters. Some of them don't work any more because of boost evolving, but unfortunately there are no test cases to detect that systematically.

I tested the multi_index_container some more, so now I am including it here. I set its version to 1.42 because that's the oldest boost version I tested it with, but it works with 1.46 and 1.55, too. I added a basic test & use case under examples.

The printers are loaded ok with gdb 7.0, 7.4 and 7.6. Again, I hope they work but unfortunately I don't have test cases. The multi index printer works only in 7.4 and 7.6 because in 7.0 I cannot capture the output of gdb.execute() in a string.