class metenglayout - new class acquires measurements in cm or ft-in

Derived from QHBoxlayout, this class provides one edit window to acquire
linear metric measurements in cm, and two edit windows to acquire linear
english measurements in ft and in.
phystat.pro - added metenglayout class
phystat - added metenglayout class for metric/english inputs

Did some other cleanup and commentary.  Made some objects in
phystat::createInputGroup() global to the class for access by other
functions.