hdfview

Merge pull request #61 in HDFVIEW/hdfview from ~JHENDERSON/hdfview:feature/AttributeNatTable to hdfview-3

* commit 'ea7976187d580f199157d9749913a546c005f7b9':
  Remove old special subsetting values for Text data
  Make sure Attribute table has valid selections when doing operations
  Update CompoundDSTableView to use loadData scheme
  Eliminate use of global NT variable
  Split some of the MenuBar logic into DefaultScalarDSTableView subclass
  Fix some minor logging issues
  Make Base TableView subclasses open shell to avoid weird errors on failure
  Handle invalid custom notation formats
  Move global NT variable down to ScalarDSTableView
  Fix bug where Attributes on nested objects can't be renamed
  Fix attribute renaming using wrong object path
  Allow proper display of text data in TableView
  Enable opening of Attributes in TableView