New s2dv_cube testing

Test the development of the new 's2dv_cube' structure

• Branch master

Tests list

• Test function as.s2dv_cube() with the Verification suite test in this issue tests by @aho.
• Test function as.s2dv_cube() with the Verification suite test in this issue tests by @vagudets .
• Test function CST_SaveExp
• Test other functions