* tm-monitor: tweaked formatting of start time and avg tx throughput.
* tm-monitor: update health when validator number is updated.
* Updated CHANGELOG_PENDING
* Added PR number to CHANGELOG_PENDING.
Improves `tm-monitor` formatting of start time (RFC1123 without unnecessary precision) and avg tx throughput (three decimal places). The old tx throughput display was confusing during local testing where the tx rate is low and displayed as 0.
Also updates the monitor health whenever the validator number changes. It otherwise starts with moderate health and fails to update this once it discovers the validators, leading to incorrect health reporting and invalid uptime statistics. Let me know if you would like me to submit this as a separate PR.
### Before:
```
2019-09-29 20:40:00.992834 +0200 CEST m=+0.024057059 up -92030989600.42%
Height: 2518
Avg block time: 1275.496 ms
Avg tx throughput: 0 per sec
Avg block latency: 2.464 ms
Active nodes: 4/4 (health: moderate) Validators: 4
NAME HEIGHT BLOCK LATENCY ONLINE VALIDATOR
localhost:26657 2518 0.935 ms true true
localhost:26660 2518 0.710 ms true true
localhost:26662 2518 0.708 ms true true
localhost:26664 2518 0.717 ms true true
```
### After:
```
Sun, 29 Sep 2019 20:21:59 +0200 up 100.00%
Height: 2480
Avg block time: 1361.445 ms
Avg tx throughput: 0.735 per sec
Avg block latency: 4.232 ms
Active nodes: 4/4 (health: full) Validators: 4
NAME HEIGHT BLOCK LATENCY ONLINE VALIDATOR
localhost:26657 2480 1.174 ms true true
localhost:26660 2480 1.037 ms true true
localhost:26662 2480 0.981 ms true true
localhost:26664 2480 0.995 ms true true
```
* Remove unnecessary type conversions
* Consolidate repeated strings into consts
* Clothe return statements
* Update blockchain/v1/reactor_fsm_test.go
Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>
This PR repairs linter errors seen when running the following commands:
golangci-lint run --no-config --disable-all=true --enable=unconvert
golangci-lint run --no-config --disable-all=true --enable=goconst
golangci-lint run --no-config --disable-all=true --enable=nakedret
Contributes to #3262
