Support for inline wrap definitions in build_master.json

Problem

1. Duplicate .wrap files everywhere.
2. Repeatedly need to create subprojects folder and then .wrap files.
   Overall, the process doesn't seem smooth.

Solution

    "wrap_dependencies" :
    [
        {
            "type" : "wrap-git",
            "url" : "https://github.com/ravi688/Common.git",
            "revision" : "head",
            "depth" : 1,
            "provide" :
            {
                "common_static_dep"
            }
        }
    ]

This will automatically generate .wrap files in the subprojects directory. If the subprojects directory doesn't exist then it should be created.