Support divelogs.de exports that include Cyrillic characters

divelogs.de sends us XML files that explicitly state that they are in
ISO-8859-1 encoding (which is true). These files contain the HTML encoded
Cyrillic characters. Once we decode those characters the resulting file is
actually UTF-8 encoded (which is a superset of ISO-8859-1). That seriously
confuses libxml when it tries to parse things.

So instead recognize divelogs.de files and skip the encoding declaration
for them before decoding the HTML encoded non-ISO-8859-1 characters.

This does show, however, that divelogs.de incorrectly truncates the
encoded strings (at least in some sample data that I created the parsing
throws errors because of that).

Reported-by: Sergey Starosek <sergey.starosek@gmail.com>
Based-on-code-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Use a generic 64bit int type

The zip_int64_t type appears to be missing with mingw so it breaks my cross
builds - and this is clearly equivalent.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Only print separator when really needed on import

The separator was printed if SITE had data, even if LOCATION was empty.
Now print the separator only if both of these contain data.

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Terminate decode at end of string and fix mem leak

Seems that we have to NULL terminate the buffer for
xmlStringLenDecodeEntitites() as otherwise we might end up having extra
data at the end of returned buffer.  (Somehow the length parameter is
not respected always, even if it is the proper size returned by the
zip_fread() - header_skip).

Also free the buffer returned by xmlStringLenDecodeEntitites().

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
First step towards a context menu in the profile view

This is completely bogus as all it does is print out the corresponding
time for the spot we right-clicked on the profile. But that at least shows
that the infrastructure is working as intended...

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Manually add gas changes to a dive

Create a little widget that lists all the gases / tanks we know about and
allow the user to pick one of them.

Turns out that add_event only added events at the end of the list - but we
treat that list as chronologically sorted. So I fixed that little
mis-feature as well.

This does raise the question whether we need the inverse operation
(removing a gas change). And if there are other things that we should be
able to manually edit, now that we have the infrastructure for this neat
little context menu...

See #60 -- this doesn't address all of the issues mentioned there, but at
least deals with the 'headline' of the feature request...

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>