Fix for following CPPCheck warnings
- invalidPrintfArgType
Rebased with latest develop branch w21.
Reverted modifications unrelated to printf issues.

- introduce loader_reset() that frees all memory
- resolve memory leak in loader_format_shlibpath()
- correctly handle library reload: check if a function has been
  retrieved already. Don't leak memory (strdup()), and handle multiple
  reloads of different functions from the same SO

Enhance loader to allow library version selection for executables, as ldcptest which do not use the config module.

For whatever reason most of the files had their permission
changed from 644 to 755, which is not wanted.

don't fail in library utility function, return with error code instead and let
application decide what is best on how to proceed

* check whether a library has been loaded before; in this case, don't allocate
  new memory but load from old library again
* vital parameters, previous exit_fun are checked by AssertFatal()
* structure has changed a bit to make it easier to follow (instead of nested
  ifs includes one goto to the end of the function)
* formatting has been improved

LOG_F replaced by LOG_DUMPMSG. Add a generic function to dump a buffer or message. Go on with LOG_M implementation improvement. Remove redundant options to enable/disable logs.