optimize geojson writer

Conversion from double value to char representation
is killing performance. This change replaces ostreams
with string appends to speed it up.

Change-Id: Ice0e8694deeb8898340dd7c989689aa4511c7fb4
more optimization of geojson writer

Move from strings to sprintfs to be faster still.
Requires manual buffer management of course.

From here we have to move to bson and then to
more compact representations.

Change-Id: I043fe5e4b3308449ac30092fa7128c7475ff47d8
vtkpython: add site-packages to the path

Now that mpi4py lives there, look for modules there as well.

Change-Id: I6e815a0ea31cfc264cdcf74c180f8b8d6a9aa362
import mpi4py 1.3

v=1.3
githash=f2db7face09dda17da04c5276b78095830743c3c

Source copied from ParaView's ThirdParty module.

Change-Id: I489b8e9026cd0fde3bdd4218d4e2b5ddc1f252ce
Executive was setting update extent initialized falsely.

vtkStreamingDemandDrivenPipeline was setting
UPDATE_EXTENT_INITIALIZED when updating the whole extent,
which was causing pipelines not to re-execute when extents
changes. Fixed.

Change-Id: Ic696ba7e8290f29450864b2c079a2686747e26f4
Merge branch 'mpi4py-upstream' into add-mpi4py-third-party

* mpi4py-upstream:
  import mpi4py 1.3

Change-Id: Ida86f20103ad9f5ef60e93c08a10d5d039964413
mpi4py: add module information

Change-Id: Ibf3befb2491b9a04651462a10a5dc68c515b214d
Merge topic 'add-mpi4py-third-party'

647b8907 mpi4py: add module information
f39c1284 Merge branch 'mpi4py-upstream' into add-mpi4py-third-party
aa8f6a08 import mpi4py 1.3
0843035a vtkpython: add site-packages to the path

Change-Id: I934194e8a94c4e1c16e72b59981cecc32253185d
Merge topic 'optimize-geojson' into master

0e46e310 more optimization of geojson writer
bd3c09e3 optimize geojson writer
Merge topic 'extent-initialized-fix' into master

8c0040fa Executive was setting update extent initialized falsely.
Fix python for vtkweb

Change-Id: I6138d9b067913edc4396387c45393a702dc03d08
Merge topic 'vtkweb-python-fix' into master

4c98d894 Fix python for vtkweb