Modificação nos nomes das variaveis:

Classe - ActivityMain e Drive
Correção de diversos bugs que estavam ocorrendo quando testado diretamento no celular
New contents:
* Now he can sum the income and expenses from months
* Implemented SharedPreferences
* Fixed some bugs
New contents:
* Fix a bug when we have a parcel drive and try to edit him.
* In year change, the background change the color.
New contents:
* Deleted change color for year.
* Change scale from button, to better view.
* Change background from buttons.
* Change icon for delete button.
Merge pull request #5 from kevinmelo/codigo_limpo

Codigo limpo