plscheme - plscheme: Fixed printing stuff in exception handler and added

Log Message:
-----------
Fixed printing stuff in exception handler and added ability to pass PostgreSQL
exceptions to Guile exception handler. This will be used for SPI execution
functions, which gives programmer the availability of catching spi-execute,
spi-prepare and spi-execute-prepared errors.

Modified Files:
--------------
plscheme:
plscheme.c (r1.9 -> r1.10)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plscheme/plscheme/plscheme.c.diff?r1=1.9&r2=1.10)