Moving Shoes::Swt::TextBlock related files to subdirectory
Renaming TextBlockPainter to Shoes::Swt::TextBlock::Painter
Renaming TextBlockCursorPainter to Shoes::Swt::TextBlock::CursorPainter
Move TextBlockFitter to Shoes::Swt::TextBlock::Fitter
Move FittedTextLayout -> TextSegment naming

Involved a lot more renaming of variables for context than other moves.
Moved Shoes::Swt::TextBlock spec back where it belonged
Renaming layout_height method on TextSegment
Merge branch 'master' into subdir_for_text_block

Conflicts:
	lib/shoes/swt/text_block_fitter.rb
	spec/swt_shoes/text_block/fitter_spec.rb
	spec/swt_shoes/text_block/text_segment_spec.rb
Merge pull request #723 from shoes/subdir_for_text_block

Move Swt::TextBlock related classes to subdirectory. Changelog: improvement