Use a workitems mapping file during export to convert work items ids

Introducing of `--export-work-item-mapping=` option to specify file path
How to migrate to TFS2013(Git) keeping work items association
Update Next.md
Add -I option to automatically find the remote to use

Looking in the git history, we can easily find the tfs remote we must interact with.
Using this `-I` option (instead specifying the remote name with `-i`) permit
 to automatically find the good remote and use it...
Update Next.md
Update Next.md
update doc on `-I` option
work items association
Merge pull request #506 from pmiossec/Next.md

doc
Merge remote-tracking branch 'origin/master' into p504

Conflicts:
	doc/release-notes/NEXT.md
Merge pull request #504.
Merge remote-tracking branch 'origin/master' into p498

Conflicts:
	doc/release-notes/NEXT.md
Merge pull request #498
Move release notes around for 0.19.2.
v0.19.2