Refactoring: style, improved signals for changing page/chapter, removed unused dependencies
idea files
Curvas1.py viewpoint fixes
removed file
deleted superficie reference
Merge remote branch 'renato-geomdif/master'

Conflicts:
	Curvas1.py
	curvas_superficies.py
better point of view
#25: Curvas en superficies: loxodroma. Marcar algunos meridianos
Formulas y texto en el cuadro 'Plano Tangente' (Issue #41).