fix(variable): Add 'and' in where-clause

related to CAM-941
feat(variable): Expose variable query via REST Api

- Expose variable instance query via REST api (GET/POST)

related to CAM-940
feat(count): Add count to variable instance query

related to CAM-940
chore(clean): remove uncommented code
fix(release): Maven cannot set correct version during release
chore(variable): Exclude byte types from query

- the variable instance query does not select variable instances with type
  equals 'bytes'
- Furthermore, the values of the selected variable instances will be
  fetched initially to prevent NEPs later

related to CAM-780
fix(engine): Set parent activityInstanceId

- in the case of parallel multiple subprocess containing a parallel
  gateway the running execution had the wrong activity instance id
- now the running execution has as activity instance id the activity
  instance id of the sub process (i.e. the parent activity instance id)

related to CAM-780
feat(variable): Load variable instances in cockpit

- In cockpit the current variable instances of the selected process
  instance are shown.
- On click on a bpmnElement or on an activity instance node only the
  variable instances for the current selection will be shown.
- Improve layout of cockpit
- Clean up some directives

related to CAM-780
Merge branch 'master' of github.com:camunda/camunda-bpm-platform
chore(varinst): serialversion id & formatting

- using serialVersionUID = 1L
- some formatting & cosmetics in VariableInstance.xml

related to #CAM-941
fix(var-inst): Fix race condition in variable view

related to CAM-941
chore(var-inst): Change num of variables in table

related to CAM-941
feat(sample): Add wait state example to distro
chore(db-upgrade): Remove module from distro

- remove qa-db-upgrade module from distro profile to be able to run the
  release
fix(qa-postgres-xa): Try to fix postgres-xa remote invocation bug
 Prepare release: set version to 7.0.0-alpha7
 Next development version: 7.0.0-SNAPSHOT
chore(qa-xa-tests): Remove deprecated profiles for xa-tests

related to CAM-788
Merge branch 'master' of github.com:camunda/camunda-bpm-platform
fix(qa-glassfish-xa): Support XA transaction datasources on Glassfish