Revert "remove joint/separable out of master branch"

This reverts commit 1d999bc56ea5a4abc177a40648e1033c6a6a34a0.
actually fix scat_freq bug (mult signal case)
Merge commit 'origin/master' into joint_audio
fix mult signals bug in joint
fix data_read error (textscan usage)
Merge branch 'master' into joint_audio
add git_hash
Merge remote-tracking branch 'origin/master'
fix padding problem with J = log(size(x))
doc for wavefactory 2d and 3d
fix scattergram toolbox usage (signal)
add half-sample option to pad_signal_1d & fix symmetrization (negative part)
make wavelet_2d use pad_signal_1d
split out conv_sub_2d from conv_sub_unpad_2d
add resolution to 2d scattering & incorporate when calcualting wavelet_2d
fix unpadding bug
make wavelet_1d output absolute resolution, not relative
wavelet_1d gives absolute res, not relative - update joint_layer
Merge branch 'master' into joint_audio
(un)pad_signal_1d -> (un)pad_signal