Changes to Custom MDC Parser for Custom Layout Pattern

- I have made a first pass changes to use custom layout pattern. 

- It gives the output as :
                     "properties" : {"recordAssociation":"xyz","uuid":"1000"}
- Previously it was : 
                     "properties" : "{{recordAssociation,xyz}{uuid,1000}}"


- The code may not be the most optimal solution. Looking for feedback.