Revert "Merge pull request #426 from dolanjs/doc-mat-pip-depends"

This reverts commit 0e6764add143b56450987792c42a1d7eb23fa0ef, reversing
changes made to 1d62c311c1b0df9f4aa0d825d5234b9fd0a5a836.
Revert "Merge pull request #326 from gnusosa/develop"

This reverts commit 6735ffa700d394b18dddadd581a50b628e039464, reversing
changes made to c59609dc2073686243f887f34bef4324d073144d.

Conflicts:
	.travis.yml
	install_files/source-requirements.txt
	securedrop/requirements/source-requirements.txt
	securedrop/source.py
	securedrop/source_templates/lookup.html
	securedrop/static/css/securedrop.css
	securedrop/store.py
	securedrop/tests/test_unit.py
	setup_dev.sh
Remove MAT and hachoir from apparmor rules
remove line about metadata scrubbing feature from changelog
remove python-poppler (MAT dependency)