add par_calcLatSw to build_calc_ts_needs

[aappling-usgs]

@jread-usgs this should get you

> build_calc_ts_needs(var='par', src='calcLatSw')
        var_src var_target src_target          var_src_needs coord_needs dvq_needs
1 par_calcLatSw        par  calcLatSw par_calcSw par_calcLat     lat lon          

[aappling-usgs]

hmm. appveyor and travis are both failing on getting things from SB:

  Running 'testthat.R'
Warning message:
running command '"c:/R/bin/i386/R" CMD BATCH --vanilla  "testthat.R" "testthat.Rout"' had status 1 
 ERROR
Running the tests in 'tests/testthat.R' failed.
Last 13 lines of output:
  19: sbtools_GET(url = pkg.env$url_items, ..., query = qury, session = session)
  20: handle_errors(r, url, "GET", supported_types)
  21: stop(method, " failed to ", url, ". check authorization and/or content", call. = FALSE)

  testthat results ================================================================
  OK: 102 SKIPPED: 0 FAILED: 4
  1. Error: get_ts works (@test-get_ts.R#6) 
  2. Error: internal function get_sites works for multisites (@test-list_and_get_info.R#4) 
  3. Error: list_datasets  (@test-list_and_get_info.R#15) 
  4. Error: get_site_coords works (@test-list_and_get_info.R#28) 

  Error: testthat unit tests failed
  Execution halted
* DONE
Status: 1 ERROR, 1 NOTE
See
  'C:/projects/mda-streams/mda.streams.Rcheck/00check.log'
for details.