Add 2 variables 'CC' and 'BCC" for configuration files.
Revert CC -> CC_ADD changes. Save value of ${CC} set by ~/.porttools to
CC_ORIGINAL and use it when generating Cc: field of PR form.
Fix bug that CC_ALL isn't set when ${CC_ORIGINAL} is empty.
Merge pull request #8 from yasuhirokimura/add_new_variables

Add 2 variables 'CC' and 'BCC" for configuration files.