Merge pull request #85 from timob/master

Add benchmark tests. As used by other database/sql drivers.
Update README.mkd

Include documentation section
Merge pull request #86 from porjo/patch-1

Update README.mkd
Include errno.h when build on cygwin. Closes #87
Use sqlite3_close_v2()
sqlite3_column_blob() returns NULL for zero-length BLOB
Merge pull request #89 from hattya/blob

sqlite3_column_blob() returns NULL for zero-length BLOB
Merge pull request #88 from hattya/close_v2

Use sqlite3_close_v2()
Provide more detailed error messages

Use the sqlite3_errmsg() API to retrieve more specific error
messages.

eg. Attempting to exec 'CREATE TABLE ExistingTableName (...)'
will now report 'table already exists: ExistingTableName' rather
than 'SQL logic error or missing database'
Update test expectations follow change of concrete error type
Add unit test for enhanced error reporting

Add a test to check for a useful response for a SQL
query that cannot be executed due to a constraint failure
Merge pull request #91 from robertknight/rob-extended_err_info

Provide more specific error messages