maint: remove most recursion in automake's own build system Recursive make-based build systems tend to be slower, more fragile and less faithful than "flat" ones. See Peter Miller's article "Recursive Make Considered Harmful" for more a more in-depth discussion: <http://miller.emu.id.au/pmiller/books/rmch/> While in the case of automake this isn't a big problem (given the small size of its build systems), it still creates occasional glitches and annoyances. With this change, the use of recursion in Automake's own build system is eliminated *but for the testsuite*. Converting that is a little more tricky, and better left for a later change (or series of changes). See also commit v1.11-769-gfeeb7f6 of 28-03-2012. * contrib/Makefile.am, lib/Makefile.am, m4/Makefile.am, doc/Makefile.am: Removed, their content merged ... * Makefile.am: ... here, with required adjustments and few other "opportunistic" changes. (SUBDIRS): Update. * configure.ac (AC_CONFIG_FILES): Likewise. * .gitignore: Likewise. Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>