MySQL fixes/additions/improvements

- fixed GH #187: MySQL: allow access to the underlying connection handle
- added GH #186: MySQL: support for MYSQL_SECURE_AUTH
- fixed GH #174: MySQL: 4GB allocated when reading any largetext or
largeblob field
WinCE fixes for zlib 1.2.8
fix MySQLTest info calls
updated version to 1.5.2
Solaris build
JSON Parser comment update
corrected gcc version check for warning suppresion
Merge remote-tracking branch 'upstream/develop' into develop