Issue #356 - Store surveyal time

* Create new persistent field to store surveyal time
* Parse time from the last column in the data.txt file (13)
Issue #356 - Add duration to raw data reports

* Add extra "Duration" column to the Excel file
* Write/Read duration attribute in the json response
Issue #356 - Fix encoding (UTF-8)
Issue #356 - Remove unused parameter
Issue #356 - Use numeric cells for survey duration
Issue #356 - Handle 'duration' in raw data report import

* Add duration to hash computation.
* Send/Receive duration query parameter.
* Handle duration changes in the import process.
* Ensure backwards compatibility with files without 'duration' column.
Issue #356 - Check for "|" char in 4rd column

* Detect if our 4rd column is 'duration' or a question
* Avoid checking for row number when not necessary(1st row)
Add braces to 'if' statement
Issue #356 - Check for null duration values
Issue #356 - Process headers (1st row) in the same block

* Handle the 1st row and 'continue' to the rest.
Issue #356 - Initialize surveyalTime attribute
Issue #356 - Check for surveyalTime null values
Merge branch 'feature/timing' into develop