Fixes to border-detection

- now calls marching-squares with correct column-major pixmap
- no longer fails if image touches image-borders
- added image test to ImageBorderTracer
Added search-index support for new models (instead of only-updates)
Moved test-i18n messages to separate folder;
fixed i18n test to match
Added a dependency to engine-desktop test-classes for editor testing
Moved teststyle into the hosting game, testgame.
Partially addresses #186
Incremental search, with tests.
Better indexing through scene-element recursion, image uris, term sanitatization
- images, atlases and ninepatches now have their URIs indexed
- notes are indexed (forgot to regenerate pojos in last commit)
- recursive processing of scene-elements; also looks into behaviors/effects
- more tests
- same processing (non-alphanumeric char removal) applied to indexable terms
  and to queries
Merge pull request #224 from manuel-freire/pixmap-to-polygon

Fixes to border-detection
Merge pull request #191 from manuel-freire/text-search

Text search update: index refreshed on game load, incremental search added