Problem: Cannot append a list of lines to a file.
Solution: Add the append option to writefile(). (Yasuhiro Matsumoto)
https://code.google.com/p/vim/source/detail?r=v7-4-503
-Ported old legacy test over to
test/functional/legacy/writefile_spec.lua
-Tests for mapping and signs from the original patch were removed since
they have nothing to do this with feature
Tested with: make oldtest, make test on OS X.
Signed-off-by: Perry Hung <iperry@gmail.com>
26e6bca769