Fix for #1545 - [RTM EF6] Issues mixing conventions and entity inheritance

Extends the overridable configuration parts infra. so that it handles configs created via lightweight conventions.

Work Item: 1545
Adding small unit test fix to contribution.
Merge branch 'release-6.0.0'
Update to build projects in parallel
Upgrade xUnit.net, OpenCover & ReportGenerator packages
fixing tests for Azure. CR: BriceLam
No constitutional right for binding flags... (Fix for 1634: Remove use of Type.GetMethod)

Replaced Type.GetMethod with Type.GetMethodInfo extension methods that use the modern API in .NET 4.5/.NET for Windows Store Apps, and the old API for .NET 4.
Fix nightly package versions

Currently, the build number is not making its way into the nightly package version. This is due to some refactoring that was done in the nightly build repository but never got propagated to this repository. This change brings the two repositories back in sync.
added some convention tests

Added Tests for failing conventions scenarios
Corresponding tests for the recent fix for #1545
Merge branch 'release-6.0.0'
Reversing the order in which configuration conventions are applied. Now the last conflicting convention wins, which is consistent with other conventions and fluent API.

Work item: 1629
Fixing test issue from merge.
Merge branch 'release-6.0.0'
Added basic functionality to MappingItem (Annotations, ReadOnly). Added MappingItem as base class to a few more mapping classes. Removed ILegacyMappingItem and replaced with dictionary that maps types to old names, and updated code in the hash builder to lookup into the dictionary. Renamed SetMapping to EntitySetBaseMapping. Added two unit tests.
Public surface for property mappings and unit tests
CodePlex #1633: Deterministic name uniquification behavior should deped on model builder version - Added code to sort the sets, navigation properties and derived types only if model builder version is EF6 or higher.
CodePlex #1633: Deterministic name uniquification behavior should deped on model builder version - Added code to sort the sets, navigation properties and derived types only if model builder version is EF6 or higher.
adding additional coverage for spatial
Add NuGet projects and targets and enable building symbols nuget package.