Removing some warning when compiling ledger.

 * ldg-commodities.el: use #' instead of ' for function quoting
 * ldg-exec.el: remove the fit-frame function that don't exists and do
   not use toggle-read-only to make the buffer read-only
 * ldg-report.el: use forward-line instead of next-line
Use (fit-window-to-buffer) for error reporting.
Merge pull request #169 from vanicat/t/warnings

Removing some warning when compiling ledger-mode