Updated some comments

Slicer.py

@@ -76,12 +76,12 @@ def slice_geometry(self):
         # Calculate slice thickness/number of slices parameters and infill spacing
         h = ydim.get()
         step = slice_size.get()
-        # Check for incorrect slice heights
+        # Check for incorrect slice heights (negative or zero)
         if step <= 0:
             step = 0.1
         num_steps = int(h/step)
         space = infill_space.get()
-        # Check for incorrect infill spacing
+        # Check for incorrect infill spacing (negative or zero)
         if space <= 0:
             space = 0.1
 
@@ -324,9 +324,9 @@ def output_popup():
                         'SVG Files:\n\nThe slicer outputs an SVG file for each vertical slice of the geometry for'
                         ' visualization and diagnostics of the print edge contours and infill patterns.\n\n'
                         'CSV File:\n\nThe slicer outputs a "path.csv" file describing the position of the print head'
-                        ' during printing. Each row represents an X,Y,Z coordinate in space and fourth value indicates'
-                        ' whethere the print head should be on (1) or off (0) when making the move to the position from'
-                        'its previous position.')
+                        ' during printing. Each row represents the elapsed time in seconds, the X,Y,Z coordinate in'
+                        ' space and fifth value indicates whether the print head should be on (1) or off (0) when'
+                        ' making the move to the position from its previous position.')
 
 
 # ****** Initialize Main Window ******

slice.py

@@ -84,7 +84,7 @@ def compute_points_on_z(geometry, z, xdim, ydim, zdim):
             pairs.append([line[2][0], line[2][1]])
 
         # Only need to keep point pairs (sets of 1 and 3 are not needed - these will be inherently handled by a point
-        # pair from a face somehwere else in the object geometry)
+        # pair from a face somewhere else in the object geometry)
         if len(pairs) == 2:
             # Reject points if they are the same (within tolerance) - too close together, not a path pair for printing
             if abs(pairs[0][0] - pairs[1][0]) < tol and abs(pairs[0][1] - pairs[1][1]) < tol:
@@ -161,7 +161,7 @@ def infill(pairs, direct, spacing):
         for fill_pass in range(num_passes+1):
             loc = min_pos + fill_pass*spacing  # Increment fill pass position by the infill spacing variable
             pts = []
-            # Loop over each segment in the list of countour point pairs
+            # Loop over each segment in the list of contour point pairs
             for segment in pairs:
                 # If the line falls on either side of the current fill pass line position
                 if segment[direct] < loc < segment[direct+2] or segment[direct+2] < loc < segment[direct]: