fix Issue 8651 - Slice op Slice throws exceptions (not errors), and nothrow

Array ops should work in @safe pure nothrow code
fix Issue 7848 - pure and nothrow ignored on unittest blocks
+1 Necessary for nothrow Appender
+2 address of template function that failed instantiation
fix Issue 10288 - Direct lambda call and purity inference bug
fix Issue 9628 - Lambda in foreach loop Vs. lambda in static foreach loop
+Nested template function + inference bug