fixes. Still to do: 
-  deploy my_strtoll10 in limbysql.c
- add mysql_options option to switch MYSQL_DATA_TRUNCATED on and off.


include/my_time.h:
  More calls are shared between client and server (libmysql now performs
  more intelligent date->number and number->date conversions).
  TODO: rename those which are not starting with 'my_'
include/mysql.h:
  MYSQL_BIND:
  - more elaborated comment
  - some of the ex-private members were given public names - 
    it's sometimes convenient to set bind->error to &bind->error_value.
    However Monty questions the idea, so it should be given
    more thought in future.
  - added new members to support data truncation.
  Added new return value of mysql_stmt_fetch, MYSQL_DATA_TRUNCATED.
libmysql/libmysql.c:
  - added support for data truncation during fetch
  - implementation for is_binary_compatible: now conversion functions
    are used less frequently
  - we now use number_to_datetime and TIME_to_ulonglong for date->number and
    number->date conversions
sql-common/my_time.c:
  - added implementation of date->number and number->date calls shared 
    between client and server (moved from time.cc).
sql/field.cc:
  - implemented Field_time::store_time() to better support date->time
    conversions in prepared mode. After-review fixes.
sql/field.h:
  - Field::store_time now returns int
sql/mysql_priv.h:
  - removed date->number and number->date conversion functions headers
    (moved to my_time.h)
sql/time.cc:
  - removed implementation of date->number and number->date conversion
    functions (moved to my_time.c)
tests/client_test.c:
  - added a test case for data truncation; other test cases adjusted.
  - fixed my_process_stmt_result to set STMT_ATTR_UPDATE_MAX_LENGTH (tables
    are now printed out prettier).