Changes for cross-hemisphere connectivity matrix

aparc12_probtrackx_cortical_connmat.py now supports the cross-hemisphere (xh) mode.

The aparc12_oldVer.py is created to allow quick (but hacky) roll-back to the old aparc12 ROI names (e.g., Hg --> H).

	new file:   aparc12_oldVer.py
	modified:   aparc12_probtrackx_cortical_connmat.py