Fix coverity issue in ISISRAW out-of-bounds access.

Code has been refactored to a common place in RawFileInfo and LoadISISNexus
has been updated to format the header in the same manner.
Refs #9950
Fix doxygen warning.

Refs #9950
Fix buffer overrun in isis raw header access.

Refs #9950
Merge remote-tracking branch 'origin/bugfix/9950_coverity_issues_isisraw'