Round up fractional ideal points to avoid fractional point tooltips

[cpeterso]

This PR fixes #104 and includes some small code refactoring.

I experimented with a number of options for fixing the fractional point tooltips. I tried displaying tooltips like "2.333" as "2+" or "~3", but the tooltips looked funny when the ideal burnline was clearly crossing the line at a different value.

In the end, the approach I liked best was to snap the ideal burnline itself to whole point values, so there is no such thing as "completing" a fractional number of points. However, this means the ideal burnline is no longer a straight line, which may confuse some users.

[pmclanahan]

Hmm.. I actually don't think we want the ideal line to be jagged outside of weekends. I like the tooltip rounding, and I like adding "points" to the tip, but instead of adjusting the line to hit whole number values, I like your suggestion of ~5 or @fwenzel's earlier suggestion of just disabling the tips on the ideal line. That line isn't meant for number values as much as just a visual guide to make it obvious how the sprint is going.

[cpeterso]

That makes sense. The jagged ideal line is a little distracting and it implies that the ideal line is a precise measurement instead of just a guideline. I will update my PR.

[cpeterso]

I updated this PR to round the points tooltips without "snapping" the ideal line. I didn't add a tilde to rounded points because it looked (on my smaller laptop screen) almost like a negative number: ~33 points vs -33 points :)

[pmclanahan]

Super great! :clap: Mind doing a git rebase -i master and squashing these down to a single commit? This is a nice hunk of work I'd like to have an easy reference to. Thanks again, and so sorry for the delay!

[pmclanahan]

Alternately I'm happy to do it if you don't want to or have no time.

[cpeterso]

I will rebase this PR soon.

[cpeterso]

squish! :)

[pmclanahan]

WOO! Thanks again!