fix numeric keys in array
added some unit tests for previous merge
updated CHANGELOG
fixed getAttribute for array access with a boolean or float key
added changelog entry about fixed boolean array access
improved error message for non-existent or invalid attributes
refactored getAttribute
fix test that that would not fail if no exception is thrown
added tests for array access with confusable keys

array keys like boolean, numeric but string, floats, null
further improved exception message and distinguish array_call and any_call access
rename item to attribute in the exception message because that's the term that is used in twig, e.g. the  function
updated C extension accordingly
[ext] updated PHP code documenting C code
[ext] code cleaning
[ext] improvements
[ext] fixed tabs
Merge pull request #3 from tucksaun/patch-1

Updating C extension
Debug extension is safe in a cli context
Fixed autoloader registration for tests if phpunit is installed as package together with Twig
Made macro doc clearer

Previous wording implied (to me at least) that macros *are* PHP functions.