Update neocomplcache.txt

Solicited from issue #448
Because of http://ftp.vim.org/pub/vim/patches/7.4/7.4.314
Merge pull request #476 from harciga/patch-1

Update neocomplcache.txt
change default cache directory to match neosnippets

This way both neosnippits and neocomplcache will store files
in ~/.cache

One less top level directory in $HOME to worry about avoiding for
backups
Merge pull request #478 from jrobeson/change-cache-dir

change default cache directory to match neosnippets