Allocate less things
Switch all #freeze changes to constants, namespacing them in Patterns
Renaming Patterns to Constants
Undoing the each_slice --> shift change; maybe not worth it
Addressing @jeremy's comments; this is beginning to look very nice
Merge pull request #681 from srawlins/allocate-less-things

Allocate less things

Conflicts:
	lib/mail/fields/common/common_field.rb
	lib/mail/utilities.rb