Sources that match sharplo(hi) and roundlo(hi) limits should be included

[mcara]

Currently star finding code filters out sources that have sharpness or roundness match one of the limits for these parameter, see

photutils/photutils/detection/irafstarfinder.py

Lines 580 to 583 in c15b004

	mask = ((newcat.sharpness > newcat.sharplo)
	& (newcat.sharpness < newcat.sharphi)
	& (newcat.roundness > newcat.roundlo)
	& (newcat.roundness < newcat.roundhi))

I believe the strict inequalities in the code above should be replaced with >= and <=.

Here is an example of a source that should be detected:

In [1]: import numpy as np

In [2]: from photutils import detection

In [3]: d = np.zeros((200, 200))

In [4]: x = 121
   ...: y = 98
   ...: d[y-1:y+2, x-1:x+2] = [
   ...:     [0.1, 0.6, 0.1],
   ...:     [0.6, 0.8, 0.6],
   ...:     [0.1, 0.6, 0.1],
   ...: ]

In [5]: f = detection.IRAFStarFinder(0, 2.5, roundlo=0)

In [6]: f.find_stars(d)
WARNING: NoDetectionsWarning: Sources were found, but none pass the sharpness, roundness, or peakmax criteria [photutils.detection.irafstarfinder]

In [7]: f = detection.IRAFStarFinder(0, 2.5, roundlo=-1e-12)

In [8]: f.find_stars(d)
Out[8]:
<QTable length=1>
  id  xcentroid ycentroid        fwhm            sharpness      roundness    pa    npix   peak         flux                mag
int64  float64   float64       float64            float64        float64  float64 int64 float64      float64             float64
----- --------- --------- ------------------ ------------------ --------- ------- ----- ------- ------------------ -------------------
    1     121.0      98.0 1.5698800300206328 0.6279520120082531       0.0     0.0     9     0.8 3.5999999999999996 -1.3907562519182182

That is, perfectly round stars are excluded by default.

[mcara]

The original code in IRAF includes interval ends as it chooses not to add the star to the list of detected objects if ellipticity < roundlo or elipticity > roundhi (same for sharpness). That is, if a star has, i.e., ellipticity == roundlo, it would be selected.