Handle relative dotfiles directories

The `lsrc` command (and thus the other commands, too) now supports
passing a relative directory name to `-d`. Previously, this caused only
the non-host and non-tag directories to run; now all dotfiles
directories are run for all metafiles, too.

As an example, this now works correctly:

    lsrc -d dotfiles

This still works, too:

    lsrc -d /home/mike/dotfiles

1 files changed, 4 insertions, 0 deletions

diff --git a/bin/lsrc b/bin/lsrc
index 972f54f..766aa2f 100755
--- a/bin/lsrc
+++ b/bin/lsrc
@@ -150,6 +150,10 @@ fi
 
 for DOTFILES_DIR in $DOTFILES_DIRS; do
 
+  if echo $DOTFILES_DIR | grep -vq '^/'; then
+    DOTFILES_DIR=$PWD/$DOTFILES_DIR
+  fi
+
   if [ ! -d $DOTFILES_DIR ]; then
     $VERBOSE "skipping non-existent directory: $DOTFILES_DIR" 
     continue