Change the parsed data column header for epochTime

[nitin710]

Describe the bug

• An earlier patch incorrect changed the column header in parsed files. original issue: https://github.com/EmotiBit/ofxEmotiBit/issues/113
• The parsed data has a column header that indicated epoch time. Currently, it is being called LocalTime, which is incorrect. (since there is no "localTime" since 1970)
• Currently, the original recording does not have UTC time recorded with the data. consequently, the parsed data has epoch time relative to the time zone the data is being parsed in, and not the correct original time zone the data is recorded in.
• The truely "correct" way would be to update the oscilloscope to add UTC time into the recorded time. This way, the location where the data was recorded is stored with the data recording.
• Without UTC being recorded by the Oscilloscope, there will be an existence of "epochTime" relative to the time zone where the parser is located.

Problem

• How to represent "Epoch Time relative to data parser location"