Buildslave fires SIGTERM before SIGKILL

Before forcefully killing the process, we fire a SIGTERM in case
the developer wants to capture some debugging information.
Fixes trac ticket #751.
Updates test_simple to check if process was killed by SIGTERM
Adds test_kill to buildslave tests

Adds a unit test which ensures the process will receive SIGKILL if
SIGTERM fails to end the process.
Updates relnotes to reflect new behavior

States that processes will receive a SIGTERM before
a SIGKILL
don't skip 'pylint' target on slave when master fails

On 'make pylint' make sure pylint target is run in both 'master' and
'slave' directories. Previously, the pylint target in 'slave' was
skipped if any errors where reported for 'master'.
disable some pylint 1.0.0 checks for now

Disable new failing checks that were introduced in pylint
1.0.0 release. To be fixed an enabled in the future.
Merge branch '751-fire-sigterm-before-sigkill' of git://github.com/markberger/buildbot
Merge branch 'pylint-1.0.0' of git://github.com/elmirjagudin/buildbot
Merge branch 'master' into nine