Fixpostdata

Bit change here was changing the field postData in message and request to jsonData to make it clear that the string in the field is a json formatted string.  That is the convention followed with the rest of the system.

Once this is merged, make sure to also merge the eternity-common message refactor branch on core-account.

core-site, core-donationPage, and core-beneficiary are already updated and won't compile correctly until this PR is merged.

The supporting changes for core-petition are in the ask-integration branch, so if you are doing core-petition work, just use that branch until the it is merged to master.