Cleaned up (and disabled part of) date/time/datetime format patch. One can't anymore change default read/write date/time/formats.
This is becasue the non standard datetime formats can't be compared as strings and MySQL does still a lot of datetime comparisons as strings
Changed flag argument to str_to_TIME() and get_date() from bool to uint
Removed THD from str_to_xxxx functions and Item class.
Fixed core dump when doing --print-defaults
Move some common string functions to strfunc.cc
Dates as strings are now of type my_charset_bin instead of default_charset()
Introduce IDENT_QUOTED to not have to create an extra copy of simple identifiers (all chars < 128)
Removed xxx_FORMAT_TYPE enums and replaced them with the old TIMESTAMP_xxx enums
Renamed some TIMESTAMP_xxx enums to more appropriate names
Use defines instead of integers for date/time/datetime string lengths
Added to build system and use the new my_strtoll10() function.
