changes for rc8
---------
 * <abstract>, <rights> goes back to <documentation type="abstract"> etc. make the type an enumeration, 
   with these identified (abstract changed to summary)
    funding
    rights
    history
    processing_level
    summary

  * change serviceType HTTP to HTTPServer
  * georeferncing ranges use "start" and "size" to disambiguate longitude
  * added "creator", so now "creator" and "publisher" have dataType "source"; creator gets mapped to 
    DIF "Originating Center", and publisher gets mapped to "Data Center".
  * add optional attribute on dates with this enumerations (from DC):
	created, valid, available, issued, modified 
  * add "desc" attribute to service
  * metadataType not deprecated

changes up to rc7
---------
add ESML, Gempak, video/realtime to DataFormatType enum
add Swath to DataType enum

publisher url not required
add property element to catalog
add date element to ThreddsMetadataGroup
add type element to dateFormatted element.
refactor geospatialCoverage, add resolution
add resolution to timeCoverage.

seperate timeCoverage element from type
seperate publisher element from type

add creator element, type publisherType to ThreddsMetaddataGroup
remove abstract, rights, use <documentation type="">
add documentationTypes
add HTTPServer, OpenDAP, OpenDAP-G, LAS as Service Types
add dateEnumTypes
range -> spatialRange
spatialRange origin/size
zpositive "up" or "down"

changes from 0.6 DTD
------- ------- -------

general 
  use schemas and namespaces
  change inheritence mechanism - now must use metadata inherited=true
  all enumerations also allow "non standard" values

catalog
  add expires attribute
  name is optional
  allow service elements
  allow multiple datasets

dataset
  allow any of the new metadata elements
  add harvest attribute
  add dataFormat attribute
  add dataSize attribute
  add collectionType attribute
  add authority as an element, so it can be inherited

access
  remove serviceType (no anonymous service)
  add dataFormat attribute
  add dataSize attribute

documentation
  allow any in the xhtml namespace

metadata
  add inherited attribute, default=false
  metdataType deprecated, allow any string
  allow any

dataTypeEnum
  add Trajectory

new elements
 abstract
 rights
 keyword
 project
 contributor
 geospatialCoverage
 timeCoverage
 publisher
 dateType
 dataTypeFormatted
 duration

 collectionTypeEnum
 dataFormatEnum

remove
 metadataTypEnum