Fix some readme links

[jklaise]

Some dead or missing links in the README. Also, there doesn't appear to be a developers/roadmap.md file.

[seldondev]

Mon Mar 30 14:50:42 UTC 2020
The logs for [pr-build] [1] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1636/1.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1636 --build=1

[seldondev]

Mon Mar 30 14:50:48 UTC 2020
The logs for [lint] [2] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1636/2.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1636 --build=2

[axsaucedo]

Nice one!
/approve

[seldondev]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: axsaucedo

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[seldondev]

Mon Mar 30 15:37:08 UTC 2020
The logs for [lint] [4] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1636/4.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1636 --build=4

[seldondev]

Thu Apr 2 13:48:16 UTC 2020
The logs for [lint] [6] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1636/6.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1636 --build=6

[seldondev]

Thu Apr 2 13:48:29 UTC 2020
The logs for [pr-build] [5] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-1636/5.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1636 --build=5