DOC: updated doc
OPT: made -o mandatory. fixed #217
DOC: edited usage to fix -l & -x misundestood. fixed #218
OPT: new script for checking RAM
BUG: fixed bug for linux when checking RAM. fixed #212
OPT: sct_extract_metric: use matricial form to compute ML (without using lstsq function)
DEV: corrected bug related to generation of phantom in atlas_validation
DEV: added investigations on partial volume correction
Merge remote-tracking branch 'origin/master'
DEV: added new atlas
DEV: small modifs to atlas
DOC: updated .gitignore
DEV: validate_atlas: major refactoring
DEV: new script to generate CSF and GM mask from the atlas
DEV: WM_atlas: new version of Gray's Anatomy that fills completely the white matter
DEV: updated WM atlas with CSF mask
DEV: WM atlas: updated manual masks
DEV: atlas: added CSF mask
DEV: WM atlas: output metric_label in tmp folder
DEV: WM atlas: changed name of function