Allow a space between the pipe symbol and the filter name.

In the unquoted syntax allow spaces '${rcnname | substring:1:5}'

Also added an error when the filter name is not recognised, instead of silently ignoring it.

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3357 25d90789-57f7-4ee0-8453-03a3dfeeeb22