BF+RF: "install" all the files from under mvpa2/data

Originally we did not have much of a hierarchy there but now with
openfmri layout it is infeasible to list each by hand.  So I adopted
recursive traversal code and replaced previous explicit subdirectories
specification.  We would just better release

This should resolve problems with "as installed" testing failures
detected on nibotmi boxes, e.g.

http://nipy.bic.berkeley.edu/builders/pymvpa-py2.x-sid-sparc/builds/134/steps/shell_4/logs/stdio
Merge pull request #255 from yarikoptic/master

BF+RF: "install" all the files from under mvpa2/data
RF: removed some unnecessary trailing "\" so to not confuse people
BF: even more files to be installed
BF: Few fixes for the tutorial related to the openfmri dataset

not all fixes yet...
Merge branch 'master' of github.com:PyMVPA/PyMVPA

* 'master' of github.com:PyMVPA/PyMVPA:
  BF: even more files to be installed
  RF: removed some unnecessary trailing "\" so to not confuse people
  BF+RF: "install" all the files from under mvpa2/data
ENH: Allow for loading existing datasets.
ENH: Add trial number to event specs generated from openfmri

This should make per-trial event modeling pretty straightforward.