Duncan Coutts authored Mar 13, 2016 and Mikhail Glushenkov committed Mar 17, 2016

Two kinds of round-trip test:
 * type conversion ProjectConfig -> LegcyProjectConfig and back
 * ProjectConfig -> print -> parse
The latter goes out to the config file format and back.

These tests uncovered a number of issues in our general config code.

(cherry picked from commit e36c0e7e)