RESTART MODE for GAIA like in TELEMAC-2D and TELEMAC-3D

[gaia] RESTART MODE for GAIA like in TELEMAC-2D and TELEMAC-3D First part

Partially closes #899 and #756 (closed)

Major improvements:

• automatic saving of variables in the RESTART FILE necessary to continue a GAIA computation at the wished records and not every graphic printout,
• as necessary variables are not saved in the RESULT FILE anymore (in particular at every graphic printout), this last file is smaller in size (e.g. with CO sediments),
• no loss of accuracy when continuing a computation.

New keywords:

• RECORD NUMBER FOR RESTART,
• RESTART MODE,
• RESTART FILE,
• RESTART FILE FORMAT,
• RESTART FILE PRINTOUT PERIOD,
• RECORD NUMBER IN RESTART FILE.

Examples:

• mud_conservation-t2d,
• yen-t2d (multi 1),
• littoral-t2d-tom (triple coupling).

Some reference files have been updated (due to less stored variables):

• flume_bc-t2d (coh),
• hippodrome-t2d (1COs, 1COs_vf),
• hippodrome-t3d (1CO + 4NCObs_4CO_consolidation),
• mud_conservation-t2d,
• rouse-t3d,
• tidal_flats-t3d.

NB: some continuations of computation are not currently perfect and need to be investigated (coupling TELEMAC-3D, CVSM...)