Bump minimal build qt version to 5.4.
Bump minimal build qt version to 5.4.

mne-tools/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,mne-tools/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,LorenzE/mne-cpp,LorenzE/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,chdinh/mne-cpp