Merge pull request #6 from mayralizarraga/master

Add subnettingActivity
Merge pull request #7 from mayralizarraga/master

Pureba desde Android Studio
Menu agregado (no funcionando).
Menu agregado (funcionando), diseno feo aun.
Se comenzo a crear un tema.
Design: Logo, Action Bar Color, Action Bar Title
Merge branch 'master' of https://github.com/Sealtyel/Android-Engineering-Toolbox
Cambio de activity a fragment