[FIX] fixed problems with negative sizeof values

 * affects win 32bit machines
[FIX,DOC] fix doxygen/latex compile issue with newer doxygen versions
[DOC] removed reference to class search engine as it is no longer available
Merge pull request #869 from aiche/fix/cachedmzml_x86

[FIX] fixed problems with negative sizeof values in CachedMzML
Merge pull request #870 from aiche/fix/doxygen-1.8.7-fixes

[FIX,DOC] doxygen 1.8.7 fixes