Fix TykTechnologies#1924 (TykTechnologies#1925)

Should check if JSVM enabled before loading JS files

Update version.go

`obfuscateKey` should respect `EnableKeyLogging` (TykTechnologies#1827)

Fix TykTechnologies#1826

Update version

optimise configurations

fixes TykTechnologies#1799

Set `"max_idle_connections_per_host": 500` where previously was capped at 100.
Ensure `"close_connections":false` is the default.

bug: EOF when performing response body transform

fixes: TykTechnologies#1729

Description of bug:

1. Create an API with a mock XML response e.g. `/api-a/mock`.
2. Create an API which reverse proxies to `api-a` called `abi-b`.
3. perform a response body transform on `api-b/mock` endpoint. e.g.
convert to json.

Bug:

```
ERROR outbound-transform: Error unmarshalling XML:
xml.Decoder.Token() - XML syntax error on line 167: unexpected EOF
api_id=90a1e135513946cb437b5e5111422227 path=soap
server_name=https://tyk-gateway.dev:8080/api-a/
```

Fix: In the case that we are reading XML, we use `ioutil.ReadAll`
to read the response body, and pass that to `mxj.NewMapXml`.

Lint: cleaning up repetition of `logrus.Fields`

Adds Upstart version detection and separate conf, fixes sysv script, …

…compatible service stopping

edit version expected in test response

Bump version to 2.5.4

Bump version