Additional script for tractogram

[frheault]

1) Validation script Uses the header information for checks

• Verify invalid coordinates
• Verify streamlines with 0 or 1 points
• Verify if streamlines perfectly overlap (optional)
• Save tractogram containing only valid streamlines (optional)

2) Concatenate script Support all file extensions

• Concatenate multiple tractograms together
• Should work if all dpv and dps are the same
• If not, options are present to --delete_dpp and --delete_dps to allow concatenation

[frheault]

This is not a WIP anymore. (Issue #35) @arokem