Added a simplified char column in table.txt

Added a new column in table.txt to store the simplified variant of
the character(s). This will be used by input-trad-output-simp
feature in the coming commits.

Some note to the new column:

1. The new column content are generated from Unihan database 6.3
   (latest version at 2013-11-02).

2. If a character has a kSimplifiedVariant, it will be filled to
   the new column.

3. If a character has no kSimplifiedVariant, and if it has a
   kZVariant, the kSimplifiedVariant of that kZVariant will be
   filled to the new column.

4. If the character didn't match the cases above, the character
   itself will be filled to the new column.

TODO: dbbuilder would have to change to read this new format.