Update jenkins jobs

  - add a 60 minute build timeout
  - clean the workspace up between builds
  - send build failure emails
Add a Ubuntu 12.04 hardening build for 4.1.x
Merge branch 'doc-i18n' of https://github.com/trafficserver-doc-ja/trafficserver
TS-2316: header_rewrite: unify style

Submitted by: Alexey Ivanov <aivanov@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: removed trailing spaces

Submitted by: Alexey Ivanov <aivanov@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: fixed segfaults in ConditionPath::append_value()

Submitted by: Manjesh Nilange <mnilange@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: added variable expansion support to add-header

Submitted by: Thomas Jackson <thjackso@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: fix for crash in client header condition

Submitted by: Manjesh Nilange <mnilange@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: added optional counter to each rule

Now you can count each rule's tripping by providing one or more "counter"
statements e.g::

    cond %{SEND_RESPONSE_HDR_HOOK} [AND]
    add-header X-DC "DC1"
    counter plugins.header_rewrite.POP
    counter plugins.header_rewrite.ALL

Submitted by: Alexey Ivanov <aivanov@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: added cookie-based conditions

Submitted by: Alexey Ivanov <aivanov@linkedin.com>
Sponsored by: LinkedIn
TS-2316: header_rewrite: improved documentation

Added variable expansion, counter operation and cookie condition.
Removed non-existient METHOD condition example.

Submitted by: Alexey Ivanov <aivanov@linkedin.com>
Sponsored by: LinkedIn
TS-2303

updating documentation for negative response caching
Add keep-alive documentation (including keep_alive_post_out)
Update CHANGES for TS-2303
TS-2341: Cast TSHttpStatus to int to suppress compiler warning in clang

Because TSHttpStatus is an enum and has a max value less than 599, comparing
<= of a variable of that type with a constant of that magnitude will always
return true. Casting to int removes that guarantee and thus the warning.
Fix list templating
Merge branch 'master' of https://github.com/jacksontj/trafficserver
TS-2339 Cleanup Makefile.am, fix wrong _SOURCES definitions
Added TS-2339.
Merge branch 'master' of https://github.com/SaveTheRbtz/trafficserver