Reworded sentence to remove ambiguity regarding PHPUnit versions

Signed-off-by: AntonyThorpe <antony.thorpe@budget12.com>
Changed title from "An Option" to "Symlinking the PHPUnit Binary"

Signed-off-by: AntonyThorpe <antony.thorpe@budget12.com>
Removed reference to PEAR in PHPUnit installation instructions

Removed Via PEAR section
Reworded title

Signed-off-by: AntonyThorpe <antony.thorpe@budget12.com>