Updating requirements.txt
-numpy >= 1.8
-scipy >= 1.0.0
-astropy >= 2.0
-photutils >= 0.2.2
-scikit-learn >= 0.17
-scikit-image >= 0.11
-emcee >= 2.1
-nestle
-corner >= 1.0.2
-pandas >= 0.18
+numpy ~= 1.8
+scipy ~= 1.0.0
+astropy ~= 2.0
+photutils == 0.4
+scikit-learn ~= 0.17
+scikit-image ~= 0.11
+emcee ~= 2.1
+nestle == 0.2.0
+corner ~= 1.0.2
+pandas ~= 0.18
matplotlib ~= 2.2
psutil
-pyprind
+pyprind ~= 2.11
munch
-opencv-python
+opencv-python ~= 3.4
+pytest
