updated via commands.json in redis-doc repo. Currently
use `make src/help.h` to re-generate. The following
are valid from the REPL:

  help
  help [command]
  help [group]
  help groups

ex:

  help sort
  help hash

volatile-lru maxmemory policy segfault fixed, thanks to Anthony Lauzon for reporting the problem with the patch. Original patch modified a bit in order to avoid the double lookup if the policy is allkeys-lru

added noeviction policy to redis maxmemory. ZSCORE removed from the list of commands that can't be called when we are low on memory, this command was added in the past for a stupid error.

build redis-server at the end so have a more pleasing to see Make output and the advice to run the test suite at the end.

first attempt to non blocking implementation of slave replication and SYNC bulk data download. Never compiled so far...

Now it is possible to use quoted strings in the redis.conf file accordingly to the sdssplitargs() function capabilities.