Create SWG_Ring.py

[bcohenkl55]

Sub-Wavelength Grating Ring Resonator - Improved version of "SWG_MultiBox_Ring"

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 94.56522% with 10 lines in your changes missing coverage. Please review.

Project coverage is 73.34%. Comparing base (0db1171) to head (96465f9).

Files	Patch %	Lines
...ayout/EBeam/pymacros/pcells_EBeam_Beta/SWG_Ring.py	94.87%	8 Missing :warning:
...eam/pymacros/pcells_EBeam_Beta/spiral_paperclip.py	92.85%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #293 +/- ## ========================================== + Coverage 73.00% 73.34% +0.34% ========================================== Files 93 94 +1 Lines 11284 11467 +183 ========================================== + Hits 8238 8411 +173 - Misses 3046 3056 +10 ```

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[lukasc-ubc]

Could you use the following to make the pins?

from SiEPIC.utils.layout import make_pin
make_pin(self.cell, "optA", [x,y], self.wg_width, LayerPinRecN, 0)

'''
Makes a pin that SiEPIC-Tools will recognize
cell: which cell to draw it in
name: text label for the pin
center: location, int [x,y]
w: pin width
layer: layout.layer() integer type, or string
direction = 
    0: right
    90: up
    180: left
    270: down

Units: input can be float for microns, or int for database units (typ. nm)

[bcohenkl55]

Updated. Thanks Lukas

[lukasc-ubc]

Thanks Ben.