Merge pull request #658 from christianmbrodbeck/fix-subdir

FIX plot_read_forward example:  specify subjects_dir
ENH: i/o for fiducials fiff files
ENH coreg:  add MriHeadFitter
ENH: add GUIs:  MriHeadCoreg,  FixDigHeadShape,  FindDigPoint
ENH: import shortcuts / mne.gui module
DOC
ENH: mri fitting with scaling

 - Make `MriHeadFitter` a subclass of `HeadMriFitter`
 - update giu
ENH geom: wireframe plotting (line_width=1 and lighting=False)
FIX coreg: MriHeadFitter
ENH: MRI-Head coregistration GUI
FIX: MriHeadFitter.save_all() default trans fname; HeadMriFitter raw path handling
FIX coreg
ENH: MriHeadCoreg fit & save progress bars
ENH coreg-gui: dialog text
ADD: fit_matched_pts() from t3on/tb-mne_kit2fiff
ENH: add Fiducials GUI
ENH coreg: make subject attribute public
ENH: add HeadMriCoreg GUI
ENH: add fit using fiducials to head-mri coreg
ENH Fiducials: load fiducials file as initial state