type check of relations
added test
Reuse nop closure in DatabaseEloquentBuildertest.php

Continued from https://github.com/laravel/framework/pull/2729

HHVM reuses closures if they have the same body, causing DatabaseEloquentBuilderTest::testEagerLoadRelationsLoadTopLevelRelationships() to fail. Instead, save the closures to variables and use those.
Add back missing rparen
Stop replacing X-Frame-Options header in FrameGuard

Fix for the change discussed in #1725
Merge pull request #2764 from BastianHofmann/patch-1

Stop replacing X-Frame-Options header in FrameGuard
Merge pull request #2763 from billmn/master

Fix missing argument on missingMethod
Merge pull request #2759 from alexmalyshev/master

Reuse nop closure in DatabaseEloquentBuildertest.php
Check for empty string.
Fix bug with routing and dashes.
Add @throws fo dock block function signature
@return string was removed by error
Check for file existence.
Merge branch '4.0'
Merge pull request #2769 from semalead/throws

Add @throws docblocks to many functions
Merge pull request #2734 from anlutro-pull-requests/relationship-type-check

Type check of relations
Tweaking some code.
Use proper instance of Relation

Bugfix from @anlutro's recent PR #2734
Merge pull request #2771 from adamgoose/master

Use proper instance of Relation