Ditz issue update
Rename duk_get_magic API file
Update duk_get_current_magic() API doc
Rename duk_get_magic() to duk_get_current_magic()

The previous name conflicts with the upcoming duk_get_magic() and
duk_set_magic() calls which edit the properties of an arbitrary
function object.
Add duk_{get,set}_magic() API calls
API testcase for duk_{get,set}_magic()
Type fix for magic value cast
API docs for magic set/get
Add error cases to magic API testcase
Add a guide related magic test to API testcases
Guide documentation for magic values
Release note: magic values
Merge branch 'api-get-set-magic'