Update up() function

  - Only single-digit input accepted as parent level; anything else is
    treated as slice of parent directory name
  - Add more comments
  - Don't do `ls` after moving to parent directory
Add '/' to tmux word separators
Use smartcase for Vim
Update vimproj suite

  - Support collecting files without recursing
  - Remove vestigial constructs for Symbian source browsing
  - Use generated list of files for grep-ing
  - Use brace expansion for paths
Consider $VIMPROJ_DIR for project directories first

Try the directory pointed to by $VIMPROJ_DIR first, and then fall back
to $HOME/vimproj
Introduce functions and binds for using lgrep

Default mappings for C-n and C-p are now changed to do traverse local
quickfix lists.
Git config changes

  - Enable rerere by default
  - Use full name from now on