Correction of setIntersection's description in the cheat sheet.

setIntersection's description was the same as setDifference's, which 
seemed like an error, I think I fixed it.
Extra doc and tests for hasElaborateAssign
Fixes Issue 9339 - Uniform for enums.
Fixes Issue 8143 - Safe std.conv.to enum conversion
make nullable throw logic errors
Update std/traits.d
Re-enable unittest that is now working.
Refactor lockstep and simplify opApply string mixin generator.
Remov workaround 8763
Fixes Issue 7819 - setTimes should work on folders.
Update getTimes params and docs to reflect it supports directories.
setTimes should throw FileException on Posix.
Update std/algorithm.d

minor typo
std.base64: Fix AssertError on certain bad input
std.base64: Introduce Base64Exception
Update std/regex.d
Fixes Issue 9457 - isSorted(string) does not work.
Japanese spell check