Plugins related improvements and fixes

spads.pl: 0.11.15
  . new plugin dependencies system
  . battle context and players defeat times are now stored in end game
    data and available for plugins
  . springServerType is now shared with plugins
  . do not count UPDATEBOT lobby commands in lobby status flood
    checks
  . minor fix in plugin customization callback
    "forceCpuSpeedValue"
  . fix typo in plugin skill management (plugin skills were
    appearing as unknown skill type)

SpadsConf.pm: 0.11.4
  . plugins configuration files can now contain a preset named
    "_DEFAULT_" which will be used if default global preset
    isn't found

SpadsPluginApi.pm: 0.10
  . new plugin dependencies system, with new callback:
    "getDependencies"
  . new plugin API accessor "getSpringServerType"
  . fix "getPlugin" API plugin management function (was
    always returning current plugin)
  . minor fix in "forceCpuSpeedValue" customization
    callback

TrueSkillLimit.pm: 0.4
  . fix warnings on autoload