Added 'neovim' to the feature list, following discussion on #44
scripts/common.sh: remove a couple bashisms

This allows the scripts to work on systems that don't have /bin/bash as
/bin/sh--such as Debian.
Fix space in link
Merge pull request #79 from jdiez17/has_neovim

Added 'neovim' to the feature list, following discussion on #44
Merge pull request #85 from jszakmeister/remove-bashisms

scripts/common.sh: remove a couple bashisms
Add link to mailing list
Changed name of binary (vim -> nvim).

Also updated affected config files and test49.vim
README.md: cosmetic fixes
os_unix: add #include for libuv
os_unix: switch to libuv chdir() function
os_unix: use libuv total memory function
move libuv functions to os.c and io.c module

Despite being an io library, the functions currently implemented with
libuv include some non-I/O tasks like getting the total amount of
memory.
Create new OS module

This module will contain all functions that perform OS calls such as IO,
filesystem access, etc.
Add missing include guard to os module