Further implementation of Theme object model
Further implementation of Theme object model
Merge branch 'theme_object_model' of github.com:weshatheleopard/rubyXL into theme_object_model

Conflicts:
	lib/rubyXL/objects/simple_types.rb
Further implementation of Theme object model
Further implementation of Theme OOXML object model
Further implementation of Theme object
Merge branch 'master' of github.com:weshatheleopard/rubyXL into theme_object_model
More Theme object model additions
Fixing tests
Issue #93: adding handling of thumbnails; adding png content-type
Version bump to 2.4.2
rdoc update
Regenerate gemspec for version 2.4.2
Further implementation of Theme
Merge branch 'master' of github.com:weshatheleopard/rubyXL into theme_object_model
Further implementation of Theme OOXML
Version bump to 2.4.3
Fixing typo in the definition of TableParts node.
Regenerate gemspec for version 2.4.3
Issue #91, #98: Making sure that the file will be automatically closed immediately after it has been read