rapidjson: Add prepare scriptlet
rapidjson: Add prepare scriptlet

It is strongly recommended to rely on scons,
if not possible, this can be done differently using this script.

For more details about building IoTivity please check:

https://wiki.iotivity.org/build

The main purpose of prep.sh, is for continuous integration experiments
 for Tizen platform, but could be used for others too.

Bug: https://jira.iotivity.org/browse/IOT-1600
Change-Id: I8b07fdc4762baf403079c8816fc3017372627ef7
Signed-off-by: Philippe Coval <ff46fec9739d31cce915aabcc3a7a2c00eee4d6c@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17537
Tested-by: jenkins-iotivity <d95b56ce41a2e1ac4cecdd398defd7414407cc08@iotivity.org>
Reviewed-by: Dan Mihai <ba8e1833495515b49ded9e20cae80a8129155aa9@microsoft.com>

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