Update API keys.

Merge branch 'develop'.

Significant improvements:
- Support for Z and M ordinates is now much better, especially the XYM form.
- Updated JTS compatibility to 1.16.1

This includes multiple major changes, several of which are breaking.
Most significantly:
- Dropped support for all target frameworks other than netstandard2.0.
- GeoAPI dependency is removed.  Everything is now either here or deleted.
- Many of the major interfaces have been replaced by classes.
- Coordinate no longer holds "Z" values in the base class.
- Other breaking changes from JTS 1.16.0 and 1.16.1, most notably around WKT.

Use license expressions instead of URLs.

Work around NuGet/NuGetGallery#6948

nuget.org seems to require prerelease tags not to start with digits or hyphens, so "-A" should be close enough.
Resolves NetTopologySuite#283 again (this time, in a way that I should be able to push to nuget.org)

Merge pull request NetTopologySuite#257 from NetTopologySuite/develop

Release v1.15.1

Release v1.15.0

Added missing entries for NetStandard

TortoiseSVN auto commit: changed externals to fixed revision.

git-svn-id: http://nettopologysuite.googlecode.com/svn/tags/v1.13.3@1260 53ca42c3-9f19-0410-8ccb-b990a9bb5db6

fixed revision for externals on tag v.1.13.2

Issue: 110


git-svn-id: http://nettopologysuite.googlecode.com/svn/tags/v1.13.2@1160 53ca42c3-9f19-0410-8ccb-b990a9bb5db6