interface: Only generate double click event if mouse did not move more than a small amount

Fixes #77
Change automake rule for generating version_vcs.h to run only when in a Git repo.

This allows the version_vcs.h to be distributed in source packages and not be overwritten during compilation.
configure.ac: Add dist-xz and foreign option, and remove AUTHORS, ChangeLog and NEWS.
Bump to 0.1-rc2
Merge fixes from v0.1_rc2
Fix #109: Bug in calculation of milirary score
popup: Fix calculation of convertible knights, which would otherwise result in random sprites being drawn
Fix bugs in lists of defending serfs

game: In update_building_castle() increment castle_knights when promoting serf to knight. Also, clear inventory pointer to avoid promoting the same serf twice.
popup, serf: Fix iteration and prepending to knight list.
game: Define max number of players as GAME_MAX_PLAYER_COUNT

Fix #111: Off-by-one error in calculating knight morale
flag: Fix bug caused by missing check in flag_prioritize_pickup()
Fix #114: Allow knight in state OCCUPY ENEMY BUILDING to enter own castle

This situation should not really happen, since an enemy castle cannot be occupied (only demolished). But this fix adds the missing case anyway because it might be needed later, and because it allows the game to gracefully recover from other bugs that may cause this situation.
Fix #115: Fix gaps in drawing of statistics chart
Fix #112: serf FREE WALKING direction badly calculated when offset is negative
Bump version to 0.1-rc3
Merge bug fixes from v0.1-rc3
serf: Fix bug where knights are not added to defenders list when entering castle
serf: Avoid inifinite loop in LOST state when player does not have any land left
game: In demolish_building() disconnect flag before update land ownership

This avoids a crash when updating land ownership tries to demolish the flag.
game: Properly dismiss the serf serving the castle, when the castle is demolished

This fixes #117.
Merge fixes from release-0.1 related to demolishing castle after winning a battle there