world coordinate do not respect datawc_x1/x2

[doutriaux1]

@danlipsa we need urgently to fix the datawc_x1/x2/y1/y2 issue this affects I isolated the issue (in meshfill at least which appear in: PCMDI/pcmdi_metrics#296 ) to be coming from: https://github.com/UV-CDAT/uvcdat/blob/master/Packages/vcs/Lib/vcsvtk/meshfillpipeline.py#L53

Looking at the issue above when runnig it with the EXACT same template and datawc_x1/x2 4 times but slightly different "mesh" coordinatesI get:

MESH: -0.5 15.5 0.0 9.5
MESH: -0.5 15.0 -0.5 9.5
MESH: -0.5 15.5 -0.5 9.0
MESH: 0.0 15.5 -0.5 9.5

which leads to the ugglyness in the issues (ticks offsets, triangle on top of each others)

Another example would be:

import cdms2
import vcs
f=cdms2.open(vcs.sample_data+"/sampleCurveGrid4.nc")
s=f("sample")
x=vcs.init()
m=x.createmeshfill()
m.datawc_x1 = -20
m.datawc_x2 = 20
m.datawc_y1 = -20
m.datawc_y2 = 20
x.plot(s,m)
x.png("bad")

png, far from being the requested bounds

[danlipsa]

@doutriaux1 Could I get the original script/data from PCMDI/pcmdi_metrics#296? I have seen and solved something similar for plots of boxfill + vector. There, the bounds for boxfill data were slightly larger than the bounds for vector the vector which resulted in similar duplication of labels.

[danlipsa]

@doutriaux1 @aashish24 Does this fix the issue?
#1855