Fixes a crash when exporting RDP profile to .rdp file. Fixes #412.

Also fixes https://bugs.launchpad.net/ubuntu/+source/remmina/+bug/714011
Clipboard fixes

Clipboard is still having problems. This commit should help to avoid crashes line the one reported in issue #411
Merge pull request #415 from giox069/master

Clipboard fixes
Fix null pointer use
Merge commit 'bbe4d1a5e31f7b3cb10514e95a8cabdd12afdf59'