ps_tokudb_admin script for simplifying tokudb installation

ps_tokudb_admin script can be used to install or uninstall TokuDB plugin in PS 5.6
When started it checks for:
- if it's run by user with root privileges
- if mysqld is running with jemalloc enabled - if not it instructs user to restart server to enable jemalloc and then to run the script again
- location of my.cnf config file
- if transparent huge pages are enabled in the system which needs to be disabled for TokuDB to run (it checks in /sys/kernel/mm/transparent_hugepage/enabled)
- if TokuDB plugin is already installed

If run with --enable parameter it:
- disables the THP for the current session in /sys/kernel/mm/transparent_hugepage/enabled so that TokuDB plugin can be enabled without restart.
- sets the thp-setting=never in [mysqld_safe] part of my.cnf so that mysqld_safe.sh script can read it and set it before starting mysql server so that TokuDB doesn't complain
- installs the TokuDB plugin in mysql

If run with --disable parameter it:
- removes the thp-setting=never from my.cnf
- uninstalls the TokuDB plugin from my.cnf

Commands for install/uninstall are send with mysql client and user,password,socket,host and port parameters are passed to it from command line.

Changes are added into mysqld_safe.sh script to read thp-setting parameter from my.cnf and set THP setting on the system.