the substrate solver can correctly work in this version

- FIX : fix a bug building SimpleONO doesn't get layer material from global control
- ENH : the applied gate voltage at contact is set when buiding the contact
- NEW : complete the substrate solver
integrate the substrate solver into solver pack. solver pack runs correctly.

- NEW : add method to get the vertices of specific contact.
- CHG : set the gate potential when building the structure, using gate voltage and workfunction
- ENH : read the channel potential as the input of Poisson solver
- CHG : the calculation of flatband voltage shift is a stand-alone method currently
- NEW : add the method for writing substrate result
- NEW : the fermi energy above substrate conduction band and channel potential is calculated using substrate solver and transferred to certain solver
add V-model for electron capture by trap and some revison of the parameters

- NEW : add V-model of electron capture coefficient
- CHG : use V-model as default model for trap capture