Fixed warnings when using the Intel Composer XE 2013 (sp1.1.106) with -Wall -w2 -Wcheck

The only notable change is that typelist accessors now take signed integer indices rather than unsigned integers.
This is required in order to obtain well-defined behavior when returning negative numbers as error codes.

Reported-by: Markus Bina <bina(at)iue.tuwien.ac.at>