Fixes the column position when invoking idetools.

Vim starts counting columns from 1 but the nimrod idetools command
starts from zero. This can be verified writing a call to the quit() proc
with a two level identation and trying to invoke idetools on the
whitespace before the word.
Merge pull request #3 from gradha/pr_fix_column_position_for_idetools

Fixes the column position when invoking idetools.