Take out all the dllimport/libraryimport out of LogExpert.Core.

[RandallFlagg]

Take out all the dllimport/libraryimport out of LogExpert.Core.
If possible, change them to safe code.

@Hirogen Please make this a sub issue of #356.

[Hirogen]

I rather finish the separation PR and start a new one for this, because it gets quite big, and reviewing 300+ files is quite difficult