[PATCH] Improved adding images

[Jan Darowski]

Hi!
Here are my two commits for improving images addition. Main goal was
to add some feedback when photos aren't in dives time range (they
cannot be added then) as discussed with Tomaz.

During my work it appeared that some refactor in images timestamps
code was needed. Miika mentioned that we can eventually need another
way of getting timestamtps so I completely seperated it.

Right now I can see two issues:
1) I'm not sure if the type of warning I wrote is right. It can be
easily changed by anyone.
2) EXIF funtions were located in qthelper.c. I also put there code of
the timestamp extraction but I'm not sure if these things should be
there... It's quiet unintuitive for me.

Greetings,
Jan Darowski
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Refactored-image-timestamp-checking.patch
Type: text/x-patch
Size: 6096 bytes
Desc: not available
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20150314/07fc922d/attachment.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0002-Added-warning-when-not-all-images-can-be-added.patch
Type: text/x-patch
Size: 5615 bytes
Desc: not available
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20150314/07fc922d/attachment-0001.bin>