Solved PL-159
RestAPI v3: revised UserResource
 - added unit tests
 - adapted classes and fixed methods
RestAPI v3: fine-tuned class annotation to avoid Jersey warnings
restapiv3 batch of fixes to swagger doc
Fixed Core-493: XML serialization needs support for UTF-8
Code cleaning in the expression engine
Core-488 Allow relocation of data folder outsite the application, for example in Dropbox
Revised REST Marketplace API:
 - added several methods
 - fixed model annotation
 - added some more test cases
RestAPI v3: removed duplicate paths in marketplace resource
Merge branch 'udphelper' of https://github.com/mcicolella/freedomotic into udphelper
udphelper added nested thread class for server