making changes for supporting oid format

[Vibaswan]

Support for OID pattern: Can be used with as format for normal properties as well as in x-field-pattern sample:

     oid:
       type: string
       format: oid
       x-field-uid: 9

     OidPattern:
      description: Test oid pattern
      type: object
      properties:
        oid:
          x-field-pattern:
            format: oid
            default: "0.1"
          x-field-uid: 1

Validation imposed:

• A string separated by . with minimum segments of two
• Each and every segment of the string should be numeric
• Each number should be in the range of 0 to 2^32-1