avoid too large regexes, try to fix #199

Let the token type scheme.Word decide on instantiation which token type
really to instantiat, by looking at the word lists, instead of creating
the regexes directly from the (long) word lists.
Revert "avoid too large regexes, try to fix #199"
I was too quick, the state.follow() stuff could break subtly by this.

This reverts commit 502e347c6a2be5b183a655dfcbed84fc4896b664.
multiple Token classes in Parser may have same regexp

It is now possible for multiple token types in a Parsers items list to have
the same rx attribute. In this case the token type test_match() method is
called for all but the last one in the list. The first one returning true is
used.
use the new possibility in slexer for multiple token types to have the same rx and use test_match() to distinghuish token type based on word lists, avoiding too long regexps.
add inf and nan to scheme number
typo nl.po