MMS a number of updates.

Following a number of newer documents (MMS CDF Format guide and MMS SDC Developer guide) a number of updates are introduced.
1. SITL is considers a DataMode by FIELDS. This was clearified by E-mail.. (although it is not stated as such in the MMS CDF Format guide). This affects naming and final location of the CDF files.
2. SITL and SRVY (survey) CDF files are to only have month as bottommost directories, others will have day. (ie. mms1/sdp/SITL/l1b/YYYY/MM/ compared with mms2/sdp/fast/ql/YYYY/MM/DD ).
3. Gitversion numbering of irfu-matlab is placed as CDF globalAttrib Generated_by in each CDF file.
4. PI_affiliation SWRI (not SwRI as was stated in skeleton files).
5. Global attrib Parents as the filename part (not path, not extention).
6. Variables only accepted as CDF_REAL4, CDF_INT2 or CDF_UINT2.
7. Error codes 1-2, 126-165, 255 are not to be used by Matlab code (reserved for bath error codes). Also code 166 is reserved for SDC scripts.

mexa64 files are once again compliled on Brain.
Merge branch 'devel' of github.com:irfu/irfu-matlab into devel