Respect specified order of fields, add option for tile_id for 1x1 vector export

[dmannarino]

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Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

• If one specifies fields to include in a 1x1 vector file, the fields are put in the file according to the order of the fields in the DB, rather than the order specified by the user.
• There is no option to include the tile ID of a feature

Issue Number: N/A

What is the new behavior?

• If one specifies fields to include in a 1x1 vector file, they are included in the order specified by the user
• There is an option to include the tile_id in which each feature lies

Does this introduce a breaking change?

• Yes
• No

Other information

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b63f243) 80.28% compared to head (63c0ab5) 80.32%.

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Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #459      +/-   ##
===========================================
+ Coverage    80.28%   80.32%   +0.03%     
===========================================
  Files          124      124              
  Lines         5509     5515       +6     
===========================================
+ Hits          4423     4430       +7     
+ Misses        1086     1085       -1     

Flag	Coverage Δ
unittests	80.32% <100.00%> (+0.03%)	⬆️

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[danscales]

Looks good. Nice that you fixed up a bunch of comments, and also added several tests!