fix bug: only iterate over actual array elements

skip undefined values in JSON input

2.0.0-beta.3

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* rename main source file to `jxon.js`
* bugfixes
* code style improvements

re-add browserify ignore xmldom statement

prerelease for 2.0.0:

* sane defaults
* Dates stringified in ISO format
* better xmlns handling on node and browser

1.6.1

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hotfix for breaking dependency upgrade (lock xmldom to v0.1.19)

1.6.0

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* expose error handling of xmldom via option parameter (for nodejs)

1.5.6

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* handle null values in JSON (same as empty object)

1.5.5

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* fix xml namespaced element creation regression #19

1.5.4

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* fix browserify compatibility regression #18