Issue #235: Unrealized gain calculated with too much precision; affects display context (blais/beancount)

[Martin Michlmayr]

New issue 235: Unrealized gain calculated with too much precision; affects display context
https://bitbucket.org/blais/beancount/issues/235/unrealized-gain-calculated-with-too-much

Martin Michlmayr:

This might be the same as bug #234 but I'm not sure and it's probably easier to merge two bugs than to split them if they are separate.

The unrealized gains plugin calculates the unrealized gains to too much precision, which also affects the display context for that commodity.

In the example below, I get an unrealized gain of 60.6180 GBP rather than 60.62 GBP.

I know I have {113.6367 GBP} in there but my understanding is that a cost should not affect the display context.

Example:

```
option "operating_currency" "GBP"

option "inferred_tolerance_default" "GBP:0.01"

2018-01-01 open Assets:Investments:III-ISA
2018-01-01 open Equity:Opening-Balance

plugin "beancount.plugins.unrealized" "Unrealized"

2018-01-01 * "Opening balance: Interactive Investor ISA GB00BPN5P782" #opening-balance
fund: "GB00BPN5P782"
Assets:Investments:III-ISA 15.99 GB00BPN5P782 {113.6367 GBP}
Equity:Opening-Balance -1817.05 GBP

2018-03-13 price GB00BPN5P782 109.8457 GBP
```

Output:

```
Assets:Investments:III-ISA 15.99 GB00BPN5P782 {113.6367 GBP}
Equity:Opening-Balance -1817.05 GBP
Assets:Investments:III-ISA:Unrealized -60.6180 GBP
Income:Investments:III-ISA:Unrealized 60.6180 GBP
```