Revert "Merge branch 'fix_hdr_axis'"

This reverts commit dfc9e6b47bc7b93f11646fd2d34f2322501ba002, reversing
changes made to 93fa008b159361157c2685a3a8b14248a1d910a8.

Conflicts:
	pyrf/gui/gui.py
Merge remote-tracking branch 'pyrf/master' into move-mode-box

Conflicts:
	pyrf/gui/frequency_controls.py