Add an :uppercase convert_symbols_to formula
Merge pull request #19 from razum2um/master

Attempt#2: support for explicit node attributes using keys beginning with "@"
Merge pull request #17 from cdinger/master

uppercase convert_symbols_to formula
renamed the :uppercase formula to :upcase
updated the changelog [ci skip]
preparing v0.5.0
added Gyoku.xml_tag and a :converter option

getting rid of global state. instead of defining Gyoku.convert_symbols_to,
you can now set the :key_converter option.

custom converters are not supported right now.
preparing v1.0.0
Clone hash node value due to rubys shallow copy of hashes.
Added spec.
Changed to old hash syntax in spec.
Test modified.
Merge pull request #21 from camol/master

Cloning node value when hash
updated the changelog
fix key_converter example in docs
Merge pull request #23 from fcheung/fix_key_converter_docs

fix key_converter example in docs
Update Gemfile to use https
rename LICENSE to MIT-LICENSE. closes #24.
add support of array of attributes