Fix Issue 6408 - string[].init gives a wrong type

Allow reinterpreting a slice or index expression as a dynamic array, static array, or associative array
redo pull #1179
test case output
fix seg fault
Merge pull request #1526 from WalterBright/b23

Redo of pull #1179
Merge pull request #1495 from yebblies/issue6408

Fix Issue 6408 - string[].init gives a wrong type
json test case from pull #1179
Merge pull request #1527 from WalterBright/b24

json test case from pull #1179
Merge pull request #1457 from 9rnsr/fix9259

Issue 9259 - Passing an array of pointers to a typesafe vararg is broken
Add `bool isv` parameter to Dsymbol::mangle()
fix Issue 8847 - voldemort + inout confuses "is"