Replaced 644 mode for new crontab files by 600

Use 600 mode for crontab files in cronjob function to avoid this error:
" (root) INSECURE MODE (mode 0600 expected) (crontabs/root)"
Merge pull request #468 from rd2b/master

cfengine_stdlib.cf: Change mode for cron files to 600
Fix segfault in process matching code

If 'ps' prints something to the stderr (probably from the dynamic linker), this infromation used to be read as a process information which very likely caused a crash. In order to avoid it, do not capture stderr from 'ps'.
Fix ips package method.

This repairs the ips package method to better target the package list
format which would, on occaision, completely miss correctly installed
packages due to regex misses.
Merge pull request #471 from bahamat/master

cfengine_stdlib.cf: Fix for ips package method not recognizing installed packages
Clarify IPS package versioning format requirements

A note about Solaris 11.1 versioning format:

  $ pkg list -v --no-refresh zsh
  FMRI                                                                         IFO
  pkg://solaris/shell/zsh@4.3.17,5.11-0.175.1.0.0.24.0:20120904T174236Z        i--
  name--------- |<----->| |/________________________\|
  version---------------- |\                        /|

Notice that the publisher and timestamp aren't used. And that the package
version then must have the commas replaced by underscores.

Thus,

    4.3.17,5.11-0.175.1.0.0.24.0

Becomes:

    4.3.17_5.11-0.175.1.0.0.24.0

Therefore, a properly formatted package promise looks like this:

   "shell/zsh"
     package_policy  => "addupdate",
     package_method  => ips,
     package_select  => ">=",
     package_version => "4.3.17_5.11-0.175.1.0.0.24.0";
Merge pull request #475 from bahamat/master

cfengine_stdlib.cf: Clarify IPS package versioning format requirements
Add freebsd support to cronjob bundle
Merge pull request #476 from rpoyner/master

cfengine_stdlib.cf: freebsd support in cronjob bundle
Adding yum_group package_method
Constify attributes.[ch]
Simplify checks for THIS_AGENT_TYPE == AGENT_TYPE_COMMON
Simplify seeding random number generator
Remove unused hash algorithms
Get rid of useless GetHash wrapper
Move [Xml]CompareToFile to cf-agent, not used in libpromises
Split files_hashes.h

This module contained two unrelated functionalities:

- File checksum database implementation (moved to cf-agent)
- Generic hash function utilities (left as is)
De-EvalContext-ify LoadFileAs{ItemList,XmlDoc}

Context was only used for calling cfPS, and all callers of those
functions either were not interested in setting promise outcome
or re-set promise outcome immediately anyway.
De-EvalContext-ify GetParentDirectoryCopy
De-EvalContext-ify mon_temp.c