Star-chart-spherical-projection

**Add a New Star to Existing Data with newStar Class**
- Users can now add new stars (fix to [Issue 1](https://github.com/cyschneck/Star-Chart-Spherical-Projection/issues/1))
- Two methods to add new stars to a plotStereographicProjection() and finalPositionOfStars()
1. newStar(starName=None, ra=None, dec=None, properMotionSpeed=None, properMotionAngle=None, magnitudeVisual=None)
- A new star with a proper motion speed and a proper motion angle
3. newStar(starName=None, ra=None, dec=None, properMotionSpeedRA=None, properMotionSpeedDec=None, magnitudeVisual=None)
- A new star with the proper motion speed for right ascension and declination

**userListOfStars -> builtInStars**
- Renamed argument `userListOfStars` to `builtInStars`

**New argument to plotStereographicProjection()**
- userDefinedStars: List of newStar objects of stars the user has added
- onlyDisplayUserStars: Only display the stars defined by the users (userDefinedStars)

**New argument to plotStereographicProjection()**
- userDefinedStars: List of newStar objects of stars the user has added
- onlyDisplayUserStars: Only display the stars defined by the users (userDefinedStars)
- save_to_csv: CSV filename and location to save final star positions with headers ["Star Name", "Right Ascension (HH.MM.SS)", "Declination (DD.SS)"]

**New Built-In Star**
- Thuban with updated star_data.csv

_Bug fixes and README.md edits_
_New pytest for additional arguments: 141 tests_

82 error handling pytests for:

- finalPositionOfStars()
- plotSterographicProjection()

- Release for new function: finalPositionOfStars() returns a dictionary of the position of stars
- Update to README for edits

Set up maxMagnitudeFilter optional flag and adds additional stars (total = 107)

Bug fix: BCE = -2000 years ago

if yearSince2000 >= -2000: year_bce_ce = "{0} C.E".format(yearSince2000 + 2000) postive years for C.E
if yearSince2000 < -2000: year_bce_ce = "{0} B.C.E".format(abs(yearSince2000 + 2000)) negative years for B.C.E

New optional argument for generating charts "showPlot" (defaults to True) that triggers plt.show(). Can turn off showing plot, useful for running multiple charts at once

plotStereographicProjection(userListOfStars=[],
northOrSouth=None,
declination_min=None,
yearSince2000=0,
displayStarNamesLabels=True,
displayDeclinationNumbers=True,
incrementBy=10,
isPrecessionIncluded=True,
showPlot=True,
fig_plot_title=None,
fig_plot_color="C0",
figsize_n=12,
figsize_dpi=100,
save_plot_name=None)