Redmine #6180: Introduce libyaml integration.

With readyaml() and parseyaml() functions.

Based on pull request #2028 in CFEngine core repository.
Modified by Kristian Amlie <kristian.amlie@cfengine.com>
Fix test which broke after regenerating plucked.cf.sub.

We can't use the "run" prefix, because the stdlib in masterfiles (and
hence plucked.cf.sub) contains bundles starting with "run".
Fix crash when package_add_command is missing.

When using packages promise and not defining 'package_add_command'
agent crashes. This fixes crash.
Merge pull request #2057 from maciejmrowiec/master

Initialize buffer before passing into sscanf. If sscanf don't match the ...
Merge pull request #2059 from pasinskim/master

Fix crash when package_add_command is missing.
Add: Discovery of Redhat Enterprise ComputeNodes

This allows successful identification of redhat compute nodes.

Ref: https://dev.cfengine.com/issues/3148
Merge pull request #2061 from nickanderson/redmine/3148

Add: Discovery of Redhat Enterprise ComputeNodes
Add: Acceptance test for list expansion

This tests that a variable can contain the name of a list and it will
expand properly if that variable is double dereferenced.

"list" slist => { "1", "2", "3" };
"list_ref" string => "bundle.list";
$($(list_ref)) == $(list)
Add extra acceptance test for parseyaml abuse.
Merge pull request #2054 from kacfengine/libyaml

Redmine #6180: Introduce libyaml integration.
Add FreeBSD specific versions of the GetProcessState and GetProcessStartTime
functions (Redmine #2330)
When checking the process state on FreeBSD, return PROCESS_STATE_RUNNING if
the state is SZOMB
Return false in GetProcessStat if sysctl does not return 0
Add parenthesis to sizeof to confirm to preferred code style
Don't cast pid as an int
Merge branch 'redmine_2330'
Update changelog for Redmine #2330.
Temporarily work around misleading text on the home page.

It appears to grab the changelog from the development branch, instead
of the tag of the latest release.
Invalid write of newline in MakeTemporaryBundleFromTemplate
Fix make dist.
Merge pull request #2063 from nickanderson/redmine/6866

Add: Acceptance test for variable expansion
Add client_history_timeout attribute to common hub control.

Redmine: #6669