util::plugin is throwing an error when a symbol is not found

[sithhell]

Currently, when loading components, we check for specific symbol in the shared libraries of components. If a symbol is not found, util::plugin throws. This is annoying when trying to debug an application were an exception is thrown with gdb. You usually do a "catch throw", unfortunately, this will also catch those exceptions from util::plugin.

The suggestion would be to use the error_code technique as done in other places already, for example the parcelport.

[sithhell]

The following gist contains backtraces to occurrences of those thrown exceptions:
https://gist.github.com/sithhell/5768768