all :ApexTest variations with specified Class name must pickup modified files as well as specified class

this is to make sure that even if test class has not been modified it is still included in the deployment package
documentation update - add : ApexStageAddOpen to the main :ApexStage overview
make sure that blank line in Stage buffer is not treated as a file to deploy
do not mark files as 'deployed' if deploy mode was 'checkOnly'
fixed bug - No such variable: "g:APEX_STAGE_BUF_NUM"
handler.afterDelete was missing in "After" trigger template