BUG: Fix invalid call to GetDataType() when vtkPoints is NULL

When desired output precision is DEFAULT_PRECISION and the input
is empty, this prevents GetDataType() from being called on a
NULL vtkPoints instance.

Change-Id: I10e1fd8db008c015f1c96ece33007e35273329c4
Merge topic 'update_vtk_master' into pv-master

341ba10 Merge remote-tracking branch 'pvvtk/pv-master' into HEAD
ed69e31 Merge topic 'light-const' into master
35e341d Marked a few API parameters as const
b2ed335 Merge topic 'fix-origin-shift-zooming' into master
2e14ebe Merge topic 'add-generic-web-testing-module' into master
6e5d249 Merge topic 'CMake-Deprecated' into master
f7c1d7d Merge topic 'fix_reduce_table_bug' into master
8b400ce Merge topic 'initialize-vars' into master
a15f812 Merge topic 'dead-code-removal' into master
af57bed Merge topic 'vtkweb-fix-filebrowser-on-webkit' into master
f1ccc96 Fix WebKit issue with attribute selector using ‘type’ as attribute name.
8d41aea ENH: Update CMake deprecated commands with new equivalents
790c9a2 Initialize unused variables when setting event
74057f3 BUG: Fixed a bug with zooming in charts
e86c7af eliminate unused variable warning
05c33b7 Removed dead code identified by -Wunused-function
...
Merge remote-tracking branch 'pvvtk/pv-master' into HEAD

* pvvtk/pv-master:

Change-Id: Ic590d891cfa194b1ed00f5eb961ef3e6edd2e65b
Merge topic 'fix-desired-output-precision-empty-input' into master

399b31f7 BUG: Fix invalid call to GetDataType() when vtkPoints is NULL
Made some float* parameters const

Change-Id: Ic15b7892ed0b07d2e0acba8b8b28758307b63cc8
Changed method declarations slightly from * to [] style

The explicit size gives the user more information as
to acceptible values.

Change-Id: I7baa5dbca7f1b6edbb67ca3139abefea6aebd02f
Added const to a few more APIs

Change-Id: I54d1c6d87be3131e5418f919acb5a629347c894c
Merge topic 'const-improvements' into master

e17528fd Added const to a few more APIs
37c1e4a7 Changed method declarations slightly from * to [] style
ed664cec Made some float* parameters const