Fix bug 7648 comment in `std.stdio.File` and add bug section to `std.file.slurp`.

Issue URL: http://d.puremagic.com/issues/show_bug.cgi?id=7648
Fix Issue 9616 - SortedRange should support all range kinds
Improved error messages
Fix Issue 9616 - SortedRange should support all range kinds
Improved error messages
review
rebased, fixed conflict
Added the text of the failing unittest
Re-implement hasIndirections

Avoids requesting the RepresentationTypeTuple of T unless really needed.

Partially solves 12000:
https://d.puremagic.com/issues/show_bug.cgi?id=12000

Fix Issue 12000 - Forward reference issue with RefCounted
safe pure nothrow sort and sum
Fix appender's extend
Cover 12428
Introduce UTF Matchers into std.uni.

It's a step zero to get decode-less std.regex.
UTF matchers are efficient functors around a set of
specific tries. Enables processing Unicode characters
without decoding at speeds on par with decoding itself.

Along the way make staticIota at 'package' protected and reuse it.

Fix a shameful typo in setSearcher.
workaround stable sort (std.move) not CTFE-able
const/pure annotations
purify std.uni constructs, blocked by std.algortihm.sort
@safety bags for utfMatchers

Granularity is horribly high. Auto-inference for templates has the
downside that it, leaves no explanations or reasons for failure.
fold in review comments
hide subMatcher until its API and utility is proven
test both narrow strings and range of char for matcher trait