infra: show version tags in /proc/sys/mars/version
brick_mem: improve debugging messages
monitoring: mars-status update, add zabbix template

- add zabbix template, cronjob and config
testing: remove old files
test_suite: Documentation and minor bugs
test_suite: current state
test_suite: adjust path names
test_suite: to calculate checksums take mars size of data device
doc: update graphics
doc: correct SPLIT BRAIN resolution
doc: new LCA2014 slides
light: fix endless creation of holes in emergency mode
light: fix use of wrong logfile after primary --force
light: always use designated primary as sync source
marsadm: remove superfluous connect links
marsadm: prevent mutual overwrite of delete symlinks

Add an (unused) host context. Previously, concurrent
log-delete operations triggered by cron could lead to
unnecessary loss of deletetion symlinks.
light: prevent races between deletions and re-erected objects
marsadm: wait for deletions after leave-resource
marsadm: reject invalidate earlier when no primary is designated
marsadm: do resource checks only once per command