Log Message:
Update pear-MDB2_Driver_mysql to 1.5.0b4 and add LICENSE.

Changelog:

- Make varchar_max_length property public, Bug #19582.
- Revert 327099 by afz, caused "Notice: Undefined index: charset on line \ 
1003"
- PEAR::isError() -> MDB2::isError(), Bug #19491.
- PEAR::loadExtension() -> extension_loaded(), Bug #19583.
- max value for VARCHAR is 65535 but if used multi-bytes (UTF8) so it is 21844,
  because UTF8 string takes 3bytes
- Fix Bug #19262. Updates conditional stagements to use logical operators to
  include MDB2_FETCHMODE_OBJECT where appropriate. Was broken in r321197.
- Have truncateTable() return MDB2_OK on success, as documented (bug 19201)
- Have alterTable() return MDB2_OK on success, as documented (bug 19200)
- Have dropIndex() return MDB2_OK on success, as documented (bug 19198)
- Have vacuum() return MDB2_OK on success, as documented (bug 19196)
- Have createIndex() return MDB2_OK on success, as documented (bug 19195)
- Have dropConstraint() return MDB2_OK on success, as documented (bug 19194)
- Have dropSequence() return MDB2_OK on success, as documented (bug 19191).
- Make setOption('result_wrap_class') actually useful by changing the default
  value of $result_wrap_class parameters from false to true.
- Obtain error information in _doQuery() because standaloneQuery() throws off
  $this->connection.
- FETCHMODE constants are NOT bitwise.
- Make $sql_comments public (was before, used in tests, no real harm).
- Property visibility
- boolean data type
- fixed bug #17984: Error is not reported when mysqli_stmt_bind_param() fails
  [dennylin93]
- fixed bug #18057: Result of getDeclaration() can have invalid syntax
  [hschletz]
- request #18068: mapNativeDatatype() returns decimal places also for 'float'
  mdb2type
- fixed bug #18203: Type introspection breaks with associative arrays if names
  are identical (patch by Peter Bex)
- fixed bug #17892: removed debug message [pdt256]
- fixed bug #18057: Result of getDeclaration() can have invalid syntax
  [hschletz]
- request #18068: mapNativeDatatype() returns decimal places also for 'float'
  mdb2type

open todo items:
- use a trigger to emulate setting default now()