Clean up .gitignore files

Sort the contents and update .gitignore files to hide generated files from
git status output.
Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>

.gitignore

 *.deps
+*.jpg
+*.la
+*.lo
 *.o
-*.so
 *.pc
-*.jpg
+*.so
+*.swp
 *~
-aclocal.m4
-autom4te.cache/
-config.log
-config.status
-configure
-config.mk
+.libs
+/aclocal.m4
+/autom4te.cache
+/config.guess
+/config.h
+/config.h.in
+/config.log
+/config.mk
+/config.status
+/config.sub
+/configure
+/depcomp
+/install-sh
+/libtool
+/ltmain.sh
+/missing
+/stamp-h1
+Makefile
+Makefile.in

clients/.gitignore

-gears
+dnd
 flower
+gears
+image
+screenshooter-client-protocol.h
+screenshooter-protocol.c
 screenshot
+smoke
 terminal
-image
 view

compositor/.gitignore

+compositor
+screenshooter-protocol.c
+screenshooter-server-protocol.h

m4/.gitignore

+libtool.m4
+ltoptions.m4
+ltsugar.m4
+ltversion.m4
+lt~obsolete.m4

wayland/.gitignore

+scanner
+wayland-client-protocol.h
+wayland-protocol.c
+wayland-server-protocol.h