[FIXED JENKINS-16474]

Fixed the HTTP request thread saturation problem with Winstone.
(cherry picked from commit 4b1a95f23f19c57d8cf48ea0b1b30aaee541db27)

Conflicts:

	changelog.html
integrating new installers
(cherry picked from commit aaf1bf29e630ad251efc21b962987d8d2be32f6d)

Conflicts:

	changelog.html
	war/pom.xml
[SECURITY-54]

Jesse's original patch
(cherry picked from commit 01a24e2cb1e885895c35fdf409c4305dcd877cd8)
[SECURITY-54] Massaging the original fix.

- Use the proper block cipher mode.
  Or else the information about the plain text still ends up revealing as a pattern without the attacker knowing the key.
- No need to hide SLAVE_SECRET from the encrypted payload.
  jnlpMac is needed to decrypt this payload to begin with, so there's no point in hiding it. This simplifies the code a little bit.
- Using a newer slave installer that uses the -secret option
(cherry picked from commit f4496df19e36465ae8d7cfebc6cde75f2888585b)