major revision on the structure of tunneling-related solver (TunnelSolver, SubsToTrapElecTunnel, TrapToGateElecTunnel)

- ENH : enhance the structure of tunneling-related solver
- ENH : move the initialization method of tunneling solver from derived class to base class
- ENH : enhance the method of calculating tunneling current
- NEW : add new method to obtain the band structure of tunneling oxide / trapping / blocking oxide
- NEW : add new method to set the tunneling tag for trapping layer boundary
tiny revision based on last commit

- CHG : change the name of some vectors
- FIX : fig a bug in finding Band-to-Trap vertex
add Trap-to-Band tunneling mechanism in SubsToGateTunnelSolver

- ENH : enhance the method for getting transmission coefficient in TunnelSolver
- NEW : add Trap-to-Band mechanism
add the mechanism of trap-to-band tunneling out

- NEW : add new material parameter, electron trap-to-band tunneling out frequency
- NEW : add corresponding methods to read and process T2B frequency
- NEW : add the method of normalization frequency
- ENH : enhance trap solver to consider this mechanism
- ENH : enhance solver pack to consider this mechanism
add the switch of Band-to-Trap and Trap-to-Band tunneling mechanism

- ENH : enhance physics switch
tiny revision based on last commit

- ENH : enhance the calculation of Trap-to-Band tunneling out
on the way of adding retention, but failed to operate at retention mode

- NEW : add the parameter for forcing the traps to be filled in debugging retention
- ENH : enhance the structure of tunnel solver
- ENH : add tunneling direction to check the tunnel direction of tunneling oxide (different in program and retention)
- ENH : the solver pack can make judge of the situation of the tunneling oxide (program / retention)
retention mode can be simulated in current version, but only tunneling out in conduction band

- ENH : enhance the method in base solver to calculate DT/FN tunneling
- CHG : delete the statement to set tunnel tag when loading the band structure
add Trap-to-Band in retention

- CHG : does not use default start time
- ENH : consider the tunneling out of two direction of trap in Trap-to-Band tunneling
- NEW : add the switch for Trap-to-Band tunneling
on the way to add 2D distribution of traps
Merge branch 'AddRetention' and on the way of adding 2D distribution of traps