Update install script

- Create script to symlink files
- Update install script to use script
- Create git config files to link (includes: gitattributes, gitignore &
  gitmessage)
- Create bash config files to link (includes: bashrc, bash_profile,
  inputrc, jshintrc, & wgetrc)
- Create basic bash config files to source from bash_profile (includes:
  bash_aliases, bash/git/grunt completions, bash_exports, bash_options,
  bash $PATH, bash $PROMPT

Issue: #4