chore(maven): prepare for maven central release

related to CAM-1250
docs(cycle/aspects): document login and threadsafe aspects
chore(maven-settings): add nexus-settings.xml to settings folder
feat(engine): Extend historicVariableInstance query with more parameters

- it is possible to use taskId and executionId as parameter for
  historicVariableInstance query
- adjust REST api for this engine api change

related to #CAM-1391
Merge branch 'master' of github.com:camunda/camunda-bpm-platform
chore(HistVarInstQuery): Remove unnecessary where clause

related to CAM-1391
chore(HistVarInstQuery/NullCheck): Provide a null check

- if "null" will be passed as parameter into
  HistoricVariableInstanceQuery#taskIdIn or
  HistoricVariableInstanceQuery#executionIdIn an exception will be thrown

related to CAM-1391
fix(engine): Fix intermediate throwing compensation with activityRef for task activities

related to #CAM-1410
feat(JobDef/Suspension): Show suspended job definitions on diagram

* JobDefinition SuspensionState:
  - if a process definition has suspended job definitions, those job
    definitions will be marked as suspended with a suspended badge on the
    diagram
  - If the process definition will be suspended, then existings job
    definitions will be marked as suspended on diagram.
  - it is possible to select an activity which has an active job
    definition.

* Plugin mechanism:
  - add the possibility to declare data plugins, which are providing user
    specified data without any view
  - with this data plugin it is possible to share data, without loading it
    twice
  - refactoring of the plugin services; add a new PluginProvider which
    will be used by the ViewsProvider and DataProvider to register and get
    plugin providers

* Refactorings (Dashboard/ProcessDefinition/ProcessInstance):
  - adjust other views which are now using the data plugin too
  - fix selection on process definition and instance view

related to CAM-1470, CAM-1555
Merge branch 'master' of github.com:camunda/camunda-bpm-platform
chore(pagination/jobDefTab/cockpit): remove pagination from tab

related to CAM-1470
chore(suspension/badge): unify badges to show the suspended state

related to CAM-1470
fix(suspension/WAS): Refactor setter to "setSuspended()"

- change SuspensionStateDto#setState() to
  SuspensionStateDto#setSuspended()
- add new profile "was-compatility" to run REST API tests with Jackson 1.6.2

related to CAM-1595
feat(increment/job/retry): Increment retries of specific failed job

- Increment the number of retries of a corresponding failed job of a
  selected incident from type "failedJob"

related to CAM-1558
fix(engine): Disallow message events with empty message names

Disallow empty - null or blank - message names

Closes CAM-1448
fix(bpmn/compensationEvent): Use the correct scope for compensation event

When the intermediate throwing compensation event has an event
subprocess as scope, it is necessary to use the parent scope of the
event sub process to find the given activiti of the main process from
the activiyRef attribute.

related to #CAM-1409
fix(engine): Add deleted code.

related to #CAM-1448
fix(testcase): Fix test case for history level NONE

related to #CAM-1409
fix(callactivity/expression): Use #{...} as expression in calledElement

related to #CAM-1490
chore(cdi/jsf): Rename TaskForm to FoxTaskForm

related to #CAM-1609