[3267] Use local #include directives

Some files were using #include <full/path/to/header> syntax which is
not desirable as the directory may move about in the source tree, and
all of the files it was including are local to perfdhcp so they should
be using #include "filename.h".
[3267] Removed includes to top level
Merge branch 'trac3267'
[master] Remove obsolete usage of AC_OUTPUT

The obsolete usage of AC_OUTPUT was actually causing config.status
to be executed multiple times, which is a big waste of time. Changed
to use the correct AC_CONFIG_FILES and AC_CONFIG_COMMANDS macros
instead.
[master] Keep generate files list sorted