fixed bug with #r not loading, and set #load to only be available at the top
#105 #98 #21
Merge branch 'dev' of github.com:filipw/scriptcs into issue71

Conflicts:
	src/ScriptCs.Core/DebugFilePreProcessor.cs
	src/ScriptCs.Core/FilePreProcessor.cs
	test/ScriptCs.Core.Tests/FileProcessorTests.cs