Photonflux

- Added simulations of PN junction time constant
- Updated formatting of PN junction data storage
- Added modeling of dispersion to waveguides through group index extraction

- Updated imbalanced_MZI example with regular and undercut thermal phase shifters
- Incorporated simulation models for regular and undercut thermal phase shifters

- Added example of PN junction MZI
- Added simulations for vertical junctions, U-shaped junctions, MOSCAP junctions. Interleaved junction to come soon.
- Removed lumerical simulation files from pypi distribution
- Removed .mat files from pypi distribution (they are generated as a byproduct of lumerical simulations)

- Added lumerical simulations of heaters and their data. Models to be build later
- Updated junction file naming convention.

- Added simulation files for straight pn junction
- Updated organization of components to put related files in folders