feat #1040 Check the skin when normalizing it

This commit updates the version of atpackager, and updates
the configuration of the ATNormalizeSkin visitor to check
the skin properties while normalizing them. In case a skin
property is not correct (i.e. if it does not match the
corresponding bean in aria.widgets.AriaSkinBeans), the
build fails.

Close #1040
fix #1052 headers were declared as Object in bean

`headers` entry in request beans was declared as Object and not Map, which
meant that JsonValidator would fail when validating any non-empty
`headers` taking the RequestBeans cfg.

For consistency, `headers` are changed to `json:Map` in both related
places in CfgBeans and RequestBeans.