Add variable parsing

[LowBudgetMan]

Right now it is very difficult to test PUTs and DELETEs since creates IDs are not able to pass from test to test meaning applications need to have test data set up ahead of time. To make this easier to test and lend HungryMoose docs to looking more like workflows, we should be able to take field results from a previous test's response and send it as part of another test's request