Recording data time and Brainstorm

[Edouard2laire]

This issue is here to keep track of the progress on the project to have time data in Brainstorm, started with PR #859

IO:

• Add time information from already imported data (Recording acquisition date : save the hour and minute of the recording start #859)
• Load / export time information from standard format [datetime] Improve I/O support for time of acquisition #865

Regarding the other formats:

• Brainvision (.eeg) doesn't seem to include any information about the recording date/time. There is this line in the vhdr file: "Impedance [kOhm] at 22:51:10 :" but I am not sure if this shows when the impedence checked or when the recording was started.
• .FIF : Quote from BIDS: "It is important to note that recording dates in .fif files are represented as int32 format seconds since (or before) the Epoch (1970-01-01T00:00:00.000000 UTC). Integers in int32 format can encode values from -2,147,483,647 to +2,147,483,647. Due to this representation, the Neuromag/Elekta/MEGIN file format for MEG (.fif) does not support recording dates earlier than 1901-12-13T08:45:53.000000 UTC or later than 2038-01-19T03:14:07.000000 UTC."

Display:

• Time series: switch from seconds from recording start to actual time IO: Add support and viz for actual time in raw and imported recordings #880
• Time series: add a goto function( ex goto 04:35:00 am)

Process:

• Processes that change the time of the beginning of the file should update the acquisition date if the time is present
  [datetime] Keep track of recording time trough the different processes #868

I will try to have the majority of this done before the new year.