Use 0.02f as offset for creating source path.

This is the value used for circle and ellipse and avoid having the source
path created far away from the destination zone. That's a usability fix.
Clip & Rotate IOP: fix regression in aspect ratio calculation

Was introduced by 0a3a5574fdc9b33792fda4d29be8445545ea8a92
Make sure the current history is written before pasting some others.

This fix the following issue:
1. open an image on darkroom
2. apply some iop
3. copy and paste some iop from another image

At this stage the changes done in 2 are lost. This commit fix this issue.
Merge pull request #614 from darktable-org/path-clone-offset

Use 0.02f as offset for creating source path.
Updated Dutch translation
Merge pull request #618 from MRIG/master

Updated Dutch translation
Update French translation.
Update French translation.