Increased tolerance level in a test assertion.

The previous tolerance level caused the test to fail on some machines.
Fixed a bug in signals.clean()

The "detrend" boolean argument in clean() is an easy way to add a trend
as another confound to remove. It must be exactly equivalent to adding
a trend in the "confounds" array. This was not the case before this
commit.
Merge pull request #49 from pgervais/clean_confounds_fix

Fixed a bug in signals.clean()
Allow resampling in compute_multi_epi_mask. Associated test.
Unmask uses nifti-like images
Fix issue #48
Fix name of unmasking functions. Fix doc.
Fixed COPYING
Merge branch 'master' of github.com:nisl/tutorial
unmask_3d and unmask_nd private. unmask do the conversion to nifti
Better checking of mask integrity.
Correct error message
Correct paramter name in intersect_mask
Bug: threshold ignored in compute_multi_epi_mask
Type and comment fix.
Merge branch 'multi_mask_resample' of https://github.com/nisl/tutorial into multi_mask_resample
Doc
Merge pull request #50 from nisl/multi_mask_resample

Multi mask resample
Merge branch 'master' into roi

Conflicts:
	nisl/masking.py
	nisl/tests/test_masking.py