Fix issue #112 : Show better errors during XML file loading.

git-svn-id: http://graph-studio-next.googlecode.com/svn/trunk@252 c2f33eb2-41b2-391d-4cb4-d9d0608729ba
Fix issue #171 : Internal GRF file parser - workaround for pin numbering problems with infinite tee filter
If output pin not found during GRF parsing and name is of the form Output<integer>, look for suitable pins of lower IDs until a suitable one is found (Output<integer-1>, Output<integer-2>,..... Output0)
This is needed because disconnecting an inf tee output pin which is not the last pin deletes that pin but does not change the IDs of the pins above leaving a gap in the pin ID numbering
e.g. For example connections to Output1, Output3, Output6 need to be restored to Output1, Output2, Output3 as inf tee output pins are created when needed.

git-svn-id: http://graph-studio-next.googlecode.com/svn/trunk@253 c2f33eb2-41b2-391d-4cb4-d9d0608729ba