remove now-unnecessary python overrides

These were related to the @keepMetadata strategy which we are moving
away from.

[1720]
point mcidasv.rbi to back to IDVPATH for grid.py

and griddiag.py.
[1720]
Clean copy of visad FlatField.java

[1720]
Bring in Jon's changes from PR94

[1720]
clean copy of DerivedGridFactory from latest IDV

[1720]
Working demo case for "makeVector" formula

[1720]
clean copy of GridMath from latest IDV

[1720]
First setMetadataMap pass on DerivedGridFactory

All I did was make sure every 'new FlatField' or 'new FieldImpl'
has a corresponding 'setMetadataMap'

[1720]
First setMetadataMap pass on GridMath

do a setMetadataMap after any new FieldImpl or FlatField

[1720]
first setMetadataMap pass on GridUtil

do setMetadataMap for every new FieldImpl/FlatField

[1720]
Clean copy of ucar/visad/Util.java from latest IDV

[1720]
1st setMetadataMap pass on ucar.visad.Util

add setMetadataMap after every new FieldImpl/FlatField

[1720]
Dont need setMetadataMap after Util.clone now

[1720]
makeVector test case works now w/o "hacks"

[1720]
Merge remote-tracking branch 'upstream/master' into inq1720-september
Merge remote-tracking branch 'upstream/master' into inq1720_metadata

Conflicts:
	edu/wisc/ssec/mcidasv/resources/python/grid.py
Merge remote-tracking branch 'upstream/master' into inq1720_metadata
Merge remote-tracking branch 'upstream/master' into inq1720_metadata
Fix for 2d grids [1720]
FlatField setMetadataMap: clone, cloneFloat, ...

cloneDouble, resample.

[1720]