Handle pandas Import Properly

[ilan-gold]

Currently, installing this package requires pandas because of https://github.com/vitessce/vitessce-python/blob/master/vitessce/wrappers.py#L9

We should probably either move this import into the ATAC-seq pipeline or add it here:

vitessce-python/setup.py

Lines 147 to 158 in b785f6b

	install_requires=[
	'ipywidgets>=7.0.0',
	'hypercorn>=0.11.0',
	'ujson>=4.0.1',
	'aiofiles>=0.6.0',
	'starlette==0.14.0',
	'zarr>=2.5.0',
	'numcodecs>=0.5.7',
	'scipy>=1.2.1',
	'negspy>=0.2.24',
	'generate-tiff-offsets>=0.1.7'
	],