Added new project for portable library + .Net Core 1.0 support plus reflection fixes

[jtsoftware]

The .Net Core 1.0 target has some differences in the type reflection stuff that make it not compatible with other targets. Also, you apparently can't have a .Net Core 1.0 and a Silverlight 5.0 target in the same portable library. This addresses this by adding a new project Lex.Db.Portable.Core, plus some conditionals in the code for the different reflection calls. It appears later versions of .Net Core might fix the reflection problems, or at least make it a little closer. However, I think the Silverlight problem will not go away, which is sad for this Silverlight user.

[jtsoftware]

Note that I don't know how to test everything, so you probably want to run this through your tests. Basically it just compiles okay.

[jtsoftware]

Oops, didn't mean to close it.

[dtila]

is there any updates on this ? There are many projects that are dependant on the lex.db, and it would be useful to benefit from this update.

Is there anything that blocked from merging this ?