Fix Issue 8877 - std.encoding.transcode is extremely slow
Add std.uni.byGrapheme and std.uni.byCodePoint
Fix issue 11583.

The problem is that the assumption that the first word of a BigUint is
always non-zero is false when BigUint == biguintcore.ZERO, which is
defined to be [0]. So we need to check for that case in
BigUint.opCmp(ulong).

Also, crash-proof BigUint's invariant, since it would cause an
out-of-bounds array access if a bug causes data.length==0.
Merge pull request #1715 from quickfur/issue11583

Fix issue 11583.
Make an unit test of std.math IEEE 754-2008 compliant.

IEEE 754-2008 does not specify the sign bit of a NaN. The exceptions to this
rule are the operations copy, negate, abs and copySign. In all other cases,
the standard does not specify the sign bit (chapter 6.3 on page 35).

The unit test I like to change with this pull request assumes that the sign
bit of a NaN is propagated through the exp() computation. This assumption
violates IEEE 754-2008.

My fix is the use of abs() on the result, because this operation changes the
sign bit of a NaN in a compliant way.

There might be other places which must be fixed but this one really hurts me.
Merge pull request #1736 from JakobOvrum/graphemerange

Add std.uni.byGrapheme and std.uni.byCodePoint
Merge pull request #891 from Kozzi11/master

Fix Issue 8877 - std.encoding.transcode is extremely slow
Merge pull request #1746 from redstar/ieee

Make an unit test of std.math IEEE 754-2008 compliant.
.gitignore Makefile
Merge pull request #1748 from dawgfoto/gitignore

.gitignore Makefile