UI: VertexArrayExplorer now supports client-side element arrays and additional display options
* element count, byte offset, and base vertex can now be adjusted in the UI to better explorer the element and vertex arrays.
* If a draw call is selected, the parameters of the call are now fed into the Explorer to provide a better user interaction.
  * Note that glMultiDraw* functions are not yet supported in this manner; Instanced draws are still not fully supported.
* Improved detection of out-of-bounds cases when accessing the element or vertex arrays
* The order of UI updates is a bit complicated here. Hopefully I can clarify:
  1) The vogleditor updates the explorer with parameters of the current API call (if applicable); UI box are updated
  2) The vogleditor updates the explorer with all the VAOs and sets the current one.
  3) When a VAO is selected, the referenced buffers are collected and the column headers to show the buffers
  4) VertexArrayExplorer UI boxes are updated to reflect either the display options set from the API call, or the element count is adjusted based on the data type selected and the size of the supplied element array.
  5) The vertex array table is populated with data from the buffers, using the currently selected values in the UI
* Changing the element data type will cause the element count to change if the API call has not set display options. It will adjust to avoid indexing beyond the end of the element array. The user may further adjust the UI options, and any invalid indexing will display "Out of bounds" in the appropriate cell of the table.
Merge branch 'master' of https://github.com/ValveSoftware/vogl
Merge branch 'master' of https://github.com/ValveSoftware/vogl