Add support for honoring svg image format preference in msc

usage: make -d print dev doxygen options

This is an extension / improvement to the pull request 67 from  groleo
- make printing of -d levels more flexible (when adding a new one this is now done automatically)
- layout of the message

doxygen version 1.8.5 throws many "Internal Inconsistency" errors when parsing .idl files

A number of error messages lacked the '\n' character

usage: make -d print dev doxygen options

Signed-off-by: Adrian Negreanu <adrian.m.negreanu@intel.com>

Report details about fork() failure in logs.

When parsing a large codebase dot failed to start. Adding this line helped narrow down the issue. Increasing my VirtualBox VM RAM size worked around the issue. A proper fix would be to spawn separate processes without using fork() so they don't start with the giant address space used by the current process.

Bug 715172 - Consistently document Fortran's equivalent function bodies

Bug 719639 - @xrefitem with empty heading string

Some texts can be independent of \htmlonly / \latexonly

Bug 668424 - HTML links in RTF output are broken