FIX: typo
add IsAbsolutePath() to util.h
add SymlinkExists() to util.h
check for file existance before dlopen()
do error handling directly after dlopen()
FIX: cosmetics
always dump full error log on dlopen() failure
Merge pull request #400 from reneme/fix-dlopen_logging

FIX: Error Logging of Library Loading Mechanics

Following the ticket CVM-595 I changed the error handling around dlopen() to produce more useful output. Unfortunately dlopen() only returns NULL on error and doesn't set errno.

Note: Adds also two utility functions: SymlinkExists() and IsAbsolutePath() + test.