update Vagrantfile to allow copy-and-paste by removing quote escapes
Vagrant build script: include build-essential to work even standard Ubuntu Desktop install
add missing include
support qt4 (in addition to qt5)
untested attempt to remove Qt5-depending JSON parsing
fix FTBFS for linux (revert changes to CMakeLists.txt in fa8f27247353b9611d115163b037ac368c84a6b3)
build with Qt4 on linux
remove cruft
fix spelling
fix spelling
delete trailing whitespace