Use data, not export time, for timestamp in filenames of exported files

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Upload a track for which upload failed earlier.
2. Examine the files in /sdcard/org.openbmap.

What is the expected output? What do you see instead?
New files are created for each upload attempt, the timestamp in the filename 
reflects the export date/time.

What version of the product are you using? On what operating system?
0.7.5 on Cyanogenmod 10.1.3

Please provide any additional information below.

I would suggest basing the timestamp for the filenames on the data the file 
contains, not on export date/time. For example, use the timestamp of the first 
GPS position. The timestamp in the filename will still be monotonous, but files 
which failed to upload will not be duplicated but overwritten on the next uplad 
attempt. (Uploads may fail for a number of reasons - the phone may run out of 
battery, the network may become unavailable for a long time, storage runs out, 
the app may terminate unexpectedly...) Also, it will make it easier to identify 
files (particularly interesting if you use your GPX files for OSM).

Original issue reported on code.google.com by mich...@vonglasow.com on 4 Oct 2013 at 8:42

[GoogleCodeExporter]

Michael, confess, you're a mind-reader ( or the issues are quite obvious :D :D )
I had the same idea yesterday when working with the data..

Will be fixed with one of the next releases.

Original comment by wish7code on 4 Oct 2013 at 8:55

• Changed state: Started
• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

Fixed with r6812f9bf0a49

Original comment by wish7code on 7 Oct 2013 at 8:48

• Changed state: Fixed

[GoogleCodeExporter]

Had to update release, previous fix had a flaw in filename generation: so now 
r542e657863b8 is fine

Original comment by wish7code on 7 Oct 2013 at 6:28