Avoid ever creating .deps directory

Thanks to @jszakmeister this uses make own features.
test1.in is not a test and it must be run always

test1.in generates files like small.vim, tiny.vim, mbyte.vim, mzscheme.vim,
lua.vim which are then used by other tests. So it must be run always.
Use MAKEOVERRIDES to pass SCRIPTS/TESTNUM arguments for `make test`
Make indentation consistent: use 2-space indent always
Merge pull request #845 'Testdir and top-level Makefile improvements'
spatch to drop check after alloc/lalloc/xmalloc #690
coverity/68215: removed failed variable + dead code from f_readfile #860
move documentation output to build/doxygen
add default doxygen 1.8.6 theme files
update theme to match neovim.org
update customdoxygen.css for doxygen 1.8.7

some icon images in the html are replaced with css.
Merge #824 'Doxygen neovim.org theme'
vim-patch:7.4.298  #815

Problem:    Can't have a funcref start with "t:".
Solution:   Add "t" to the list of accepted names. (Yukihiro Nakadaira)

https://code.google.com/p/vim/source/detail?r=156f891d520e93eab5d3ce02784660fb13a3b0d3
vim-patch:7.4.301  #816

Problem:    Still a scrolling problem when loading a session file.
Solution:   Fix off-by-one mistake. (Nobuhiro Takasaki)

https://code.google.com/p/vim/source/detail?r=8cb42aa3c4957a543e5dffe307475dbab969612f
vim-patch:7.4.302  #817

Problem:    Signs placed with 'foldcolumn' set don't show up after filler
            lines.
Solution:   Take filler lines into account. (Olaf Dabrunz)

https://code.google.com/p/vim/source/detail?r=df141c80ea3a1ffcbf82d05c1314675231fcfa75
vim-patch:7.4.303  #818

Problem:    When using double-width characters the text displayed on the
            command line is sometimes truncated.
Solution:   Reset the string lenght. (Nobuhiro Takasaki)

https://code.google.com/p/vim/source/detail?r=463ef551e9f62b63ac3f85f1f297b668b14bcd09
coverity/15010: Remove dead code.  #829

In win_close_othertab: Code can never be reached because of a
logical contradiction (CWE-561).
Pointer tp cannot be NULL at this point, so conditional operator ? can
be replaced with its second expression.
Use generated declarations in cursor.h  #849