adding modjk modules

__modjk module__
A wrapper module to the modjk http api

__modjk_worker state__
A state module that allows a minion to remove/add it-self from/a modjk load balancer
with the help of the peer system and the modjk module above at the load balancer side

I find these modules very useful with using prereq states which makes continues deployment very easy...
The only problem I've encountered is how to determine if I want to load these modules so for now they are loaded by-default

for example:
```
tomcat:
  service.running:
    - enable: True

wait-4-tomcat:
  tomcat.wait:
    - timeout: 600
    - require:
      - service: tomcat

remove-from-jk:
  modjk_worker.stop:
    - name: {{ grains['id'] }}
    - lb: load balancer name
    - target: 'roles:loadbalancer'
    - expr_form: grain
    - prereq:
      - tomcat: /webapp

/webapp:
  tomcat.war_deployed:
    - war: salt://wars/webapp-1.0.war
    - require:
      - tomcat: wait-4-tomcat

add-to-jk:
  modjk_worker.activate:
    - name: {{ grains['id'] }}
    - lb: load balancer name
    - target: 'roles:loadbalancer'
    - expr_form: grain
    - require:
      - tomcat: /webapp
```