Rewriting eye tracking context and gaze analysis sections.

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+Edit timestamped gaze positions
+===============================
+
+Whatever eye data comes from a file on disk or from a live stream, timestamped gaze positions are required before going further.
+
+![Timestamped gaze positions](../../../img/timestamped_gaze_positions.png)
+
+## Import timestamped gaze positions from CSV file
+
+It is possible to load timestamped gaze positions from a [Pandas DataFrame](https://pandas.pydata.org/docs/getting_started/intro_tutorials/01_table_oriented.html#min-tut-01-tableoriented) object which can be loaded from a CSV file.
+
+```python
+from argaze import GazeFeatures
+import pandas
+
+# Load gaze positions from a CSV file into Panda Dataframe
+dataframe = pandas.read_csv('gaze_positions.csv', delimiter=",", low_memory=False)
+
+# Convert Panda dataframe into timestamped gaze positions precising the use of each specific column labels
+ts_gaze_positions = GazeFeatures.TimeStampedGazePositions.from_dataframe(dataframe, timestamp = 'Recording timestamp [ms]', x = 'Gaze point X [px]', y = 'Gaze point Y [px]')
+
+# Iterate over timestamped gaze positions
+for timestamped_gaze_position in ts_gaze_positions:
+
+	# Do something with each timestamped gaze position
+	...
+```
+
+## Edit timestamped gaze positions from live stream
+
+Real-time gaze positions can be edited thanks to the [GazePosition](../../../argaze.md/#argaze.GazeFeatures.GazePosition) class.
+Besides, timestamps can be edited from the incoming data stream or, if not available, they can be edited thanks to the Python [time package](https://docs.python.org/3/library/time.html).
+
+```python
+from argaze import GazeFeatures
+
+# Assuming to be inside the function where timestamp_µs, gaze_x and gaze_y values are catched
+...
+
+	# Define a timestamped gaze position converting microsecond timestamp into second timestamp
+	timestamped_gaze_position = GazeFeatures.GazePosition((gaze_x, gaze_y), timestamp=timestamp_µs * 1e-6)
+
+	# Do something with each timestamped gaze position
+	...
+```
+
+```python
+from argaze import GazeFeatures
+
+import time
+
+# Initialize timestamp
+start_time = time.time()
+
+# Assuming to be inside the function where only gaze_x and gaze_y values are catched (no timestamp)
+...
+
+	# Define a timestamped gaze position with millisecond timestamp
+	timestamped_gaze_position = GazeFeatures.GazePosition((gaze_x, gaze_y), timestamp=int((time.time() - start_time) * 1e3))
+
+	# Do something with each timestamped gaze position
+	...
+```
+
+!!! warning "Free time unit"
+	Timestamps can either be integers or floats, seconds, milliseconds or what ever you need. The only concern is that all time values used in further configurations have to be in the same unit.