Issue #92: allow for space row/column matrix.
Merge branch 'master' of github.com:weshatheleopard/rubyXL into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb
Merge branch 'master' of github.com:weshatheleopard/rubyXL into performance_enhancers
Merge branch 'master' of github.com:weshatheleopard/rubyXL into performance_enhancers
Merge branch 'master' of github.com:weshatheleopard/rubyXL into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb
	spec/lib/worksheet_spec.rb
Merge branch 'master' of github.com:weshatheleopard/rubyXL into performance_enhancers
Merge branch 'master' into performance_enhancers
Merge branch 'master' of github.com:weshatheleopard/rubyXL into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb
	spec/lib/worksheet_spec.rb
Merge branch 'master' into performance_enhancers
Merge branch 'master' into performance_enhancers
Merge branch 'master' into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb
Merge branch 'performance_enhancers' of github.com:weshatheleopard/rubyXL into performance_enhancers
Merge branch 'master' into performance_enhancers
Merge branch 'master' into performance_enhancers
Merge branch 'master' into performance_enhancers
Merge branch 'master' into performance_enhancers
Merge branch 'master' into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb
Merge branch 'master' into performance_enhancers

Conflicts:
	lib/rubyXL/worksheet.rb
	spec/lib/worksheet_spec.rb
Tests cleanup
Version bump to 3.3.0