Add missing Ipopt return codes. #206

# to view logs

	name: GitHub CI
	on:
	push:
	branches:
	- master
	pull_request:
	branches:
	- master
	jobs:
	osx:
	runs-on: macos-latest
	steps:
	- uses: actions/checkout@v2
	- name: Build
	run: bash tools/gha_osx.sh
	windows-2019:
	runs-on: windows-2019
	steps:
	- uses: actions/checkout@v2
	- name: Add msbuild to PATH
	uses: microsoft/setup-msbuild@v1.0.2
	- uses: conda-incubator/setup-miniconda@v2
	with:
	auto-update-conda: true
	python-version: 3.8
	channels: conda-forge
	channel-priority: strict
	- name: Build
	run: .\tools\gha_windows-2019.ps1
	shell: powershell
	build-and-deploydocs:
	if: ${{ github.event_name }} == 'push'
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: Install and Build 🔧
	run: bash tools/gha_deploydocs.sh
	- name: Upload to github pages 🚀
	if: ${{ github.event_name == 'push' }}
	uses: JamesIves/github-pages-deploy-action@v4
	with:
	folder: doc/sphinx/_build/html # The folder the action should deploy.

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