v1.2.0 NETStandard

Changes:
-Code updated for VS2017
-Added support for NET Standard 1.1, NET Standard 1.5
-Added support for NET Core 1.0, NET Core 1.1
-Fixed support to NET Core 2.0
-solutions wide code cleanup

EventInvoke added

New EventInvoke method (with overload added) that creates delegate for invoking any event.

Small fixes to v1.0

1. Support for event custom delegates types
2. Added IndexerGetNew method without not necessary return type parameter
3. IndexerSetNew without indexer item type

First nuget release

Code of first Nuget package release of version 1.0