grammar: Fix string literals in CHECK expressions (and maybe other places)

Fix parsing of table definitions like this one where there is a complex
check constraint using string literals:
CREATE TABLE "a" (
    `b` TEXT CHECK(`b`='A' or `b`='B')
);
The grammar parser would fail to parse this statement correctly prior to
this fix.

See issue #179.

src/grammar/Sqlite3Lexer.cpp

@@ -1,4 +1,4 @@
-/* $ANTLR 2.7.7 (20130425): "sqlite3.g" -> "Sqlite3Lexer.cpp"$ */
+/* $ANTLR 2.7.7 (20141010): "sqlite3.g" -> "Sqlite3Lexer.cpp"$ */
 #include "Sqlite3Lexer.hpp"
 #include <antlr/CharBuffer.hpp>
 #include <antlr/TokenStreamException.hpp>

src/grammar/Sqlite3Lexer.hpp

@@ -2,7 +2,7 @@
 #define INC_Sqlite3Lexer_hpp_
 
 #include <antlr/config.hpp>
-/* $ANTLR 2.7.7 (20130425): "sqlite3.g" -> "Sqlite3Lexer.hpp"$ */
+/* $ANTLR 2.7.7 (20141010): "sqlite3.g" -> "Sqlite3Lexer.hpp"$ */
 #include <antlr/CommonToken.hpp>
 #include <antlr/InputBuffer.hpp>
 #include <antlr/BitSet.hpp>

src/grammar/Sqlite3Parser.hpp

@@ -2,7 +2,7 @@
 #define INC_Sqlite3Parser_hpp_
 
 #include <antlr/config.hpp>
-/* $ANTLR 2.7.7 (20130425): "sqlite3.g" -> "Sqlite3Parser.hpp"$ */
+/* $ANTLR 2.7.7 (20141010): "sqlite3.g" -> "Sqlite3Parser.hpp"$ */
 #include <antlr/TokenStream.hpp>
 #include <antlr/TokenBuffer.hpp>
 #include "sqlite3TokenTypes.hpp"

src/grammar/sqlite3.g

@@ -463,7 +463,7 @@ suffixexpr
 literalvalue
   :
     NUMERIC
-//  | STRINGLITERAL // captured by columnname
+  | STRINGLITERAL
 //  | blob-literal
   | NULL_T
   | CURRENT_TIME

src/grammar/sqlite3TokenTypes.hpp

@@ -1,7 +1,7 @@
 #ifndef INC_sqlite3TokenTypes_hpp_
 #define INC_sqlite3TokenTypes_hpp_
 
-/* $ANTLR 2.7.7 (20130425): "sqlite3.g" -> "sqlite3TokenTypes.hpp"$ */
+/* $ANTLR 2.7.7 (20141010): "sqlite3.g" -> "sqlite3TokenTypes.hpp"$ */
 
 #ifndef CUSTOM_API
 # define CUSTOM_API