Relax plurals syntax - find variable automatically

[puzrin]

Current format:

#{count} active %{user|users}:count

Could be:

#{count} active %{user|users}

Rule:

• take first "yet unused" variable, if not defined strictly. Variable can be before of after plural
• the same, when several plurals/vars (very rare case, can be skipped)
• if no variable in string - take the first key from params.

[puzrin]

More simple solution: if plural's variable not defined - use count by default. That will cover 99% of cases. Good enougth.

(!) make shure, that %{user|users}: will be resolved as plural + :