Allow sharing of local working directory between plans.

From https://support.atlassian.com/browse/BSP-1006

We have multiple Plans / Projects that have common code that can be shared between them. In order to be space efficient, I would like to setup the usage of the structure whereby we can have multiple plans / projects in a structure, yet still share common code without having to have that common code "checked out" into each plan / project baseline. An example of this structure would be as follows:

Current structure used by Bamboo and Plan / Project "PlanA":

/Bamboo-home/xml-data/build-dir
===> /PlanA
======> /PlanA_SRC
======>/Shared_modules

Now, if I bring a second Plan / Project "Planb" into the picture that also uses the shared_modules:

/Bamboo-home/xml-data/build-dir
===>/PlanA
======>/PlanA_SRC
======>/Shared_modules
===> /PlanB
======>/PlanB_SRC
======>/Shared_modules

What I would like to see is the ability to setup the Bamboo-home structure whereby it uses our Shared_modules as a coomon code shared between Plans / projects