Various changes from Lyon

[rassouly]

• Add current source to the Yoko 7951
• HDF5: Add the abilities to save to multiple files in the same measurement
• HDF5: add reshape capability (from Zaki I think)
• HDF5: add the ability to skip checks
• Various small changes

[rassouly]

Could we get this merged? The only stuff that will affect other user is the HDF5 stuff and we've been using it for months now with no issues

[MatthieuDartiailh]

I mentioned this one to Marius explicitly, lets apply the same policy as on the other PR.

@leghtas @rlescanne @MVillius please have a look

[MatthieuDartiailh]

Ready to merge then @MVillius ?

[MatthieuDartiailh]

If yes approve the changes and even feel free to press the green button

[mvillius]

@MatthieuDartiailh I am fine with the last changes, but I am afraid I am not authorized to press the green button :o