Summary:
Add shellprocess to enable i386.
Bump Standards-Version to 4.5.0.
This provides "plan B" to T143
Test Plan:
1. Boot live media
1. Try to install Steam in Discover and it should fail with "dependency resolution failed"
1. Install Lubuntu
1. Reboot
1. `dpkg --print-foreign-architectures` returns `i386`
1. Install Steam in Discover and it should just work
Reviewers: wxl, tsimonq2
Reviewed By: wxl
Differential Revision: https://phab.lubuntu.me/D75