Deprecate value log

Eystein OKed it.
Merge pull request #1240 from maciejmrowiec/master

Add HasRegexMetaChars to matching lib
list folding utility functions: min, max, mean, variance
testall: run specified tests according to the defaults
testall: explicitly announce which test groups are being exercised
testall: add help options and quiet long-opt
Merge pull request #1201 from cdituri/cdituri/core/testall-enhancements

Cdituri/core/testall enhancements
Fix failure to open paths ending in a slash.

Redmine #3905.
Merge pull request #1239 from tzz/feature/list-folding-utility-functions

list folding utility functions: min, max, mean, variance
Remove unused global variables
Don't set $(match) during process selection and DeleteItem*

This causes EvalContext to disappear from significant amount of code.
Move SelectItemMatching to the place of use
Move MatchRegion to the place of use
Move a few $(match)-setting functions to cf-agent.
CFEngine functions ought not to reset $(match) context

Hence, they should not use FullTextMatch function
Move BlockTextMatch/FullTextMatch to cf-agent, as only useful there

Those functions set $(match) scope, which is only well-defined for
cf-agent (indeed, there is a check inside to only set it for
cf-agent). Hence any use of those functions outside of cf-agent
is a bug and has been eliminated.
Don't check for agent type, it's always cf-agent
Do not attempt to expand functions in the middle of an iteration
Add warning when using known problematic variables in package promise.

Discovered while writing acceptance tests for package promises, and
very hard to understand what's going on unless you get this warning.
Fix incorrect return value for empty string in safe_open.