Adds multiple-sheet manipulation w/o breaking existing API and keeping existing ability-based DSL
Adds the worksheetName property to XlsxExporter, allowing you to change the initial worksheet's name
Formalized a static prop definition like its original, downgrades Grails version
Adds support for raw Maps
Updated readme with multi-sheet info
Frigging typo. Can't unit-test readmes...
Merge branch 'master' of git://github.com/joeRinehart/excel-export into joeRinehart-master
Small fixes, in needed of a larger code review / refactoring

Conflicts:
	README.md
	src/groovy/pl/touk/excel/export/XlsxExporter.groovy
	src/groovy/pl/touk/excel/export/abilities/CellManipulationAbility.groovy
	src/groovy/pl/touk/excel/export/abilities/RowManipulationAbility.groovy
comments cleaned
sheets refactored
sheet creation more DSL friendly
updated README.md with multiplesheets and renaming default sheet