refs #10088 Failing attempt to change loading

(does not work correctly)
refs #10088 Change necessary for working without precompiled headers
refs #10088 Map is build seems correctly but detID-s are still wrong
refs #10088 Mainly done, checks and optimization is needed
refs #10088 Got rid of m_spectra_list in favor of m_specNum2SpecID map
refs #10088 Unit tests to check the changes and correct behavior

+ final bugs fixed for LoadISISNexus2
Merge branch 'bugfix/10088_PartialSpectraLoading' into develop