Merge branch 'mysql-5.6' into mysql-5.7

(cherry picked from commit 26429d55448d54c7e0ecf070956e48fdcfca603a)

Bump version

Incorporate latest approved LICENSE file

Updated README according to new condensed template.

Also updated copy for DEB packaging.

Bug#27194270: LIMIT PASSWORD HASH ROUNDS IN SHA256-CRYPT ALGORITHM

Description: Authentication string for sha256_password
             can contain an optional part specifying
             number of hash rounds to be performed.
             Though default is 5000, an
             authentication_string directly inserted
             in mysql.user table can contain different
             value. This may cause extra computations
             and may introduce unnecessary delay.

Solution: Fixed the maximum number of rounds allowed.
(cherry picked from commit b9e85dc240a1fce3e57c3d9a3be25eab7f9be606)

Revert "BUG#26985561: BACKPORT BUG#26277771 TO 5.7"

This reverts commit fce1c96b65005c78b3016e855a3e4790bd5c6449.

(cherry picked from commit a38611468f4b1c6fcb7ceace231bb097d89f0226)

Bug#27194270: LIMIT PASSWORD HASH ROUNDS IN SHA256-CRYPT ALGORITHM

Description: Authentication string for sha256_password
             can contain an optional part specifying
             number of hash rounds to be performed.
             Though default is 5000, an
             authentication_string directly inserted
             in mysql.user table can contain different
             value. This may cause extra computations
             and may introduce unnecessary delay.

Solution: Fixed the maximum number of rounds allowed.
(cherry picked from commit b9e85dc240a1fce3e57c3d9a3be25eab7f9be606)

Revert "BUG#26985561: BACKPORT BUG#26277771 TO 5.7"

This reverts commit fce1c96b65005c78b3016e855a3e4790bd5c6449.

(cherry picked from commit a38611468f4b1c6fcb7ceace231bb097d89f0226)

Bug#27194270: LIMIT PASSWORD HASH ROUNDS IN SHA256-CRYPT ALGORITHM

Description: Authentication string for sha256_password
             can contain an optional part specifying
             number of hash rounds to be performed.
             Though default is 5000, an
             authentication_string directly inserted
             in mysql.user table can contain different
             value. This may cause extra computations
             and may introduce unnecessary delay.

Solution: Fixed the maximum number of rounds allowed.
(cherry picked from commit b9e85dc240a1fce3e57c3d9a3be25eab7f9be606)

Fix build break due to the usage of std::map

Replaced std::map with Properties.

Updated copyright year in user visible text