Ruby implementation of openEHR

(In r90) refs #38, #39, #48

(In r91) refs #39

(In r92) refs #39

(In r93) refs #39
fixed UID_Based_ID

(In r94) refs #39
fixed Object_Ref, Object_ID

(In r95) refs #39
fixed Hier_Object_ID

(In r97) refs #39
locatable_ref class finished

(In r98) refs #39
fixed Party_Ref

(In r99) refs #39
fixed Access_Group_Ref

(In r100) refs #39
fixing Version_Tree_ID

(In r102) refs #39, #65

(In r106) refs #48, #52, #39

(In r107) refs #39, #48