Haxby example, this time with l1-logistic

Same example as plot_haxby_full_analysis.py, but using l1-logistic
instead. I've made two small changes to plot_haxby_full_analysis.py
to make the comparison easier to interpret: fix the vmax so that
both are in the same scale and put a title in the plot.
Rename log_l1 to different estimators
Merge branch 'pr_148'

Conflicts:
	plot_haxby_full_analysis.py
BUG: error msg in check_niimgs

The right error was raised, but for the wrong reason