issue 5224
fix Issue 10125 Unicode non-BMP decoding to dchar in stdio readln

strings were first decoded to wchars, each wchar was then separately
decoded to dchar, resulting in 2 dchars in the surrogate block instead
of 1 correct dchar.

added unit test to verify readln decoding of non-ASCII characters
Merge branch 'master' of github.com:D-Programming-Language/phobos into 5224
@blackwhale's review
@blackwhale's destruction
combine some statements
Fix issues 8435, 10118.
Hack to make BigInt's typeinfo use the correct version of opCmp.
Use typeid.getHash instead of rt.util.hash.hashOf which is not
accessible from outside druntime.
Removed empty declarations. Converted more C-style array declarations to D-style. Removed trailing whitespace
Merge remote-tracking branch 'upstream/master'
More empty declarations
Reverted implicit string concatienation changes
Don't move labeles while tired
Expand tab.
Fix @property annotations and incorrect parenthesis
Remove -property switch
Use @monarchdodra's suggestion to replace ; with {}
Revert "Use @monarchdodra's suggestion to replace ; with {}"

This reverts commit 0c706b15603c1e38a19e25903f28ae145e89874d.
Reverted some changes made to the math module