Issue #155: do not create empty container node for nil values
Version bump to 3.2.6
Updated rdoc
A bit of straightening out the code
Range splitting
Sort the ranges prior to saving
Issue #153. Damn those legacy methods.
Merge branch 'master' of github.com:weshatheleopard/rubyXL
Moving convenience methods out.
Moving convenience methods out of the core
Merge branch 'master' of github.com:weshatheleopard/rubyXL
Moving convenience methods
Issue #156
Version bump to 3.2.7
Regenerate gemspec for version 3.2.7
Merge branch 'master' into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb