games/pioneer: update to 0.0.20171001

• Remove already applied patch for assimp-4.0.0
• Move USES before USE_* per Porter's Handbook style (found by portlint)
• Add SERVERAGENT port's option
• Apply upstream patch to "Fix SAR selection of ship sizes for missions"

Note, saved games from previous version are not compatible.

Changes: https://github.com/pioneerspacesim/pioneer/blob/20171001/Changelog.txt

		https://github.com/pioneerspacesim/pioneer/compare/20170304...20171001

PR: 222823
Submitted by: lightside@gmx.com (maintainer)
MFH: 2017Q4