Improve rounding when converting between mg/dL and mmol/L

[MikePlante1]

Addresses Issue #267

Currently, Trio just rounds down when logging a manual glucose entry in mmol/L. This means that 7.6 gets logged as 7.5 because 7.6 / 0.0555 ≈ 136.9 gets rounded to 136 when Int(glucose) is performed which gets displayed as 7.5 because 136 * 0.0555 ≈ 7.5.

This PR rounds asMgdL to 0 decimal places and asMmolL to 1 decimal place which allows for more accurate rounding when converting units and back.

Here's a spreadsheet that highlights the mmol/L readings that caused mismatches: https://docs.google.com/spreadsheets/d/10ZHV7ZDd0_fjrV6k0FH1ouuqy2TSsDSBpBULE4yAFyg/edit?usp=sharing

[MikePlante1]

I've tested this with manual glucose entries, temp targets, profile overrides, and target glucose. Setting it to a known problem number (like 7.6 or 8.1) in mmol/L and then switching to mg/dL and then switching back to mmol/L.

[marionbarker]

Status:

Success

Test with dev:

• started with Trio dev, commit c04d33e
• test a few of the mmol/L values in @MikePlante1 spreadsheet
• use the log glucose screen:
  • enter 6.1, see 6.0 (109)
  • enter 11.1, see 11.1 (200)
  • enter 10.6, see 10.5 (190)

Test with PR 377

• applied patch for PR
  • requires a Product Clean Folder before building
• test same entries in the log glucose screen:
  • enter 10.6, see 10.6 (191)
  • enter 11.1, see 11.1 (200)
  • enter 6.1, see 6.1 (110)

Modify to mg/dL, add to list above the mg/dL value in parentheses.

[MikePlante1]

Note that this PR does not solve rounding issues pointed out in this comment where settings can shift up to 1 mg/dL when switching units from mg/dL to mmol/L and then back to mg/dL.

I think the best way to solve that issue would be to update Trio so all mmol/L inputs are converted to mg/dL upon entry and only converted back to mmol/L when used for display. (Work has already begun on this in a private fork)