ensure cipher memory safety
Merge pull request #190 from go-sql-driver/cipher_memsafe

ensure cipher memory safety
add test for scrambleOldPassword
Merge pull request #191 from arnehormann/oldpass-test

add test for scrambleOldPassword
Enable TCP Keepalives on TCP connections to MySQL. Add keepalivePeriod DSN
option, tests, and documentation.
changed binary date / datetime to string
no longer cache len(...)
Removed "keepalivePeriod" DSN option.  Added AUTHORS entry.
Merge pull request #194 from goodinc/master

Enable TCP Keepalives on TCP connections to MySQL
updated comments for second part of the password cipher
Merge pull request #197 from zhenjl/ciphercomment

updated comments for second part of the password cipher
Add Jian Zhen

#197
applied modulo and allocation optimizations, added test
Merge pull request #195 from arnehormann/faster-dateformat

changed binary date / datetime to string