This adds a new view mode to profiler which displays source lines and
samples that occured at those lines. This view can be opened via the
menu or by pressing CTRL-S.
It does this by mapping file names from DWARF to "/usr/src/serenity/..."
i.e. source code should be copied to /usr/src/serenity/Userland and
/usr/src/serenity/Kernel to be visible in this mode.
Currently *all* files contributing to the selected function are loaded
completely which could be a lot of data when dealing with lots of
inlined code.
