Updates variables names at Element

tipo -> type (member)
list -> variableList
Merge branch 'master' of github.com:dhiana/mna
Removes unused argument :panda_face:
Removes unnecessary argument :hamster:
Fixes vector lista initialization :beetle:

It's not limited to MAX_NAME. It's limited to MAX_NODES+1.
It's not initializing the char* maximum lenght.
It's a vector of string.
Translates variable lista as variablesList
Major Hyper Mega refactor of Element class :sweat_drops:

Reading the netlist and creating nodes, elements and variables was
really messy!

Key points of this long refactoring:
* Element is now responsible for adding it's current as a variable
* This can only be done after reading all elements for a first time
* number function was renamed for getNodeNumber
* number function received numVariables as arguments (coincidently
equals numNodes at its run time)
* Now it really receives numNodes (and increments it as needed)!
* Only after reading all elements and nodes, we start numVariables with
numNodes and then add extra current variables
* To avoid adding and later subtracting numElements, we first verify if
element is valid.
* An static member function of Element is responsible for it :relieved: