Siepic-ebeam-pdk

- fix issue with Path function; previously there was a "from pathlib import Path" which conflicted with "from pya import Path"
- SWG PCell: increase DevRec
- opt_in test label for ring resonator circuit examples

- loading library fix (import sys)
- Lumerical CML fix for ebeam_dc_halfring_straight component

- fix for CentOS7: removing ( and ) characters in filenames

fix:
- from pya import *

- library PCell reload improvements, including Waveguide
- export for fabrication function
- photonic crystal pcells

- photonic wirebond evanescent surface nanotaper cells
- updated scripted layout: test structures for double-bus ring resonator
- PCell ebeam_dc_halfring_straight: fixed netlist parameter output
- PCell Waveguide: added cellName netlist parameter
- PCell library split into individual files
- add technology name in the layout library as a meta_info variable
- re-write of the contra-directional coupler with optional sbends
- updated scripted examples: MZI and ring test structures, with "connect_cell" and "connect_pins_with_waveguide" functionality