Hand out a default for Dialog.return_events

Was probably intended this way.
Fix issues with Dialog conversion of RenameDialog

Hopefully addresses what @squiddy pointed out for 50bff9e4.
Drop a blank line

Made sense back when this was part of a thirty-line __init__.
Drop a line of cleanup code that's no longer required

We load the widget (with empty text field) from scratch whenever it is
displayed, so clearing the text right before dismissing the entire
widget doesn't make much sense here.
Fix rename gui tests

Converting to Dialog apparently made them need handlers now.
Update release tools, added script to create a linux tarball

Conflicts:
	development/create_release.sh
Fix link to (old) wiki

Will be migrated rather soon in any case, but as long as there are no
concrete plans, this might work better.
Revert "Hand out a default for Dialog.return_events"

Totally not intended this way, apparently. Broke lots of confirmation
popups. Triggered #2029 on the way. Sorry for this!
This reverts commit 162fa42bf0219137610455e23dfebfa87474afb5.
Fixes #2029
More helpful headline for map saving error popup
Commit from Unknown Horizons Translation Server by user Chris Oelmueller.: 209 of 369 strings translated (14 fuzzy).
Clean up error popup on failed quicksave

Drop unicode in gettext-wrapped strings, use format()
Merge pull request #2033 from ThePawnBreak/editor-mapsave

Editor mapsave #1935
Merge pull request #2034 from ThePawnBreak/showprice

Add price tooltip to Select Resources tab. Fixes #1637
Whitespace
Drop a few assumptions about amount of music tracks

In particular we would crash if there were three or fewer tracks
available as a whole and if the menu music tried to refresh playlist
while no menu_music existed at that point.
Now restricts the deque length such that it can hold at most one track
less than the amount of tracks available.
Merge pull request #2035 from ThePawnBreak/authors

Add ThePawnBreak to list of contributors
Add Peer Gynt Suite No. 1, Op. 46 - I. Morning

composed by Edvard Grieg, performed by the Czech National Symphony Orchestra
licensed as public domain. More details can be found at http://www.musopen.org/music/piece/1568
Handle case of no ingame music being available when menu music is

Because the menu music code relies on those tracks existing, this
is probably the best solution we can come up with.
Handle case of neither ingame nor menu music being available

Previously would throw IndexErrors when looking for `track` in an empty
sequence, now just remains silent even though the settings claim that
sound is enabled (which, as long as the sound effects exist, is true
technically).
Comment and whitespace fixes