Allow quoted string attach points

Allow quoted string attach points so that you can match more than
[a-Z0-9].

This specific issue that this fixes is attaching to go
functions. These symbols are in the format '<package>.<function>' and
can contain unicode letters and digits.

src/parser.yy

@@ -142,6 +142,7 @@ attach_points : attach_points "," attach_point { $$ = $1; $1->push_back($3); }
 
 attach_point : ident               { $$ = new ast::AttachPoint($1); }
              | ident ":" wildcard  { $$ = new ast::AttachPoint($1, $3); }
+             | ident PATH STRING   { $$ = new ast::AttachPoint($1, $2.substr(1, $2.size()-2), $3); }
              | ident PATH wildcard { $$ = new ast::AttachPoint($1, $2.substr(1, $2.size()-2), $3); }
              | ident PATH INT      { $$ = new ast::AttachPoint($1, $2.substr(1, $2.size()-2), $3); }
              ;

tests/parser.cpp

@@ -457,6 +457,10 @@ TEST(Parser, uprobe)
       "Program\n"
       " uprobe:/my/program:func\n"
       "  int: 1\n");
+  test("uprobe:/my/go/program:\"pkg.func\u2C51\" { 1; }",
+      "Program\n"
+      " uprobe:/my/go/program:pkg.func\u2C51\n"
+      "  int: 1\n");
 }
 
 TEST(Parser, usdt)