Started implementing the proper error reporting.
Merge branch 'master' into parser

Conflicts:
	NSass.Tests/Lex/Tokens.cs
	NSass.Tests/NSass.Tests.csproj
	NSass/Lex/Lexer.cs
	NSass/Lex/Token.cs
	NSass/Lex/TokenTransform.cs
	NSass/Parse/IParser.cs
	NSass/Parse/ParseContextExtensions.cs
	NSass/Parse/Parselets/BodyParselet.cs
	NSass/Parse/Parselets/GroupParselet.cs
	NSass/Parse/Parser.cs
	NSass/Parse/SyntaxException.cs
Fixed a merge bug.