Reorganized project structure in order to ease building jsoncpp
(external) library.
From now on, the jsoncpp library is being built automatically with
qmake. For this to work, the top project needed to be changed to subdirs
template, and the existing source code of catalog had to be moved to
subdirectory that has been named core.
Other external libraries: POCO and boost_regex are still required and
not managed by qmake.
Adds building instructions.
Merge branch 'qmake' into develop
Bumped version to 0.3, build instructions
Merge branch 'release-0.3' into develop