Changed warning about non existing certificate directory to debug level.
Moved static Globus methods from GftpUtil to GlobusUtil. 
Default CA certificates only need to be (re)loaded when the actual proxy
is created.
Removed actual (re)load of the certificates during initialization.
Merge branch 'feature/gftp-3rdparty-copy' of github.com:NLeSC/Xenon into feature/gftp-3rdparty-copy
Merge pull request #209 from NLeSC/feature/gftp-3rdparty-copy

Fixed unnecessary warning, and updated static initialization methods.