Fix Spod Timestamp conversion

This fixed some PHP related Spod problems for me, i will ask franco to review this change.
Merge pull request #2014 from frabbit/patch-1

Fix Spod Timestamp conversion
optimize exhaustive one-case matches (closes #2019)
make @:privateAccess non-internal (closes #2020)
un-remove using field overload handling (closes #2021)
set cl_extern to false for classes having macros in macro context (closes #2015)
use unification instead of equality for array access resolution (closes #2004)
Support .ane for -swf-lib and -swf-lib-extern.

Thanks Simn, closes #2011.
document platform inconsistencies on "".split (closes #2009)
wrap abstract "this" expression if called from inside the abstract (closes #2000)