Renaming ShapeGenerator to generators

[dcoeurjo]

PR Description

this PR renames shapeGenerator folder to generators (doc updated)

Checklist

• Doxygen documentation of the code completed (classes, methods, types, members...)
• Check if it follows the tools structure described in CONTRIBUTING.md
• New entry in the ChangeLog.md added.
• Update the readme with potentially a screenshot of the tools if it applies.
• No warning raised in Debug cmake mode (otherwise, Travis C.I. will fail).

[kerautret]

good idea the renaming thanks.
Are the link ok for you ? For me not, I look to it but perhaps it is due to duplicated files with oxygen I was having bad bug about it...

[kerautret]

@dcoeurjo I fix it and I PR on you branch ;)

[dcoeurjo]

thanks a lot!
sorry for my delay.. I'm a bit swamped..

[dcoeurjo]

Fine merging I guess.. thanks again @kerautret