Added new function par_globalsetting, minor improvements to
par_reschedule_policy.
* Removed par_globalengine and par_globalpool (replaced by
par_globalsetting); also updated par_getworkers_ssh, par_clearworkers,
bci_train, bci_batchtrain, env_acquire_cluster, env_release_cluster
* Updated Java Scheduler
  - added extensive logging
  - added extra handshake with workers to improve throughput
  - improved concurrency
  - fixed consistency bug in calls to reschedule policy (event times and
event values could be out of sync)
  - randomized timeouts to avoid thread starvation
* Updated par_worker:
  - added control over the verbosity
  - added extra handshake to improve throughput
  - switched from base64 coding to fast_encode/decode (throughput
optimization)
* Updated docs of par_schedule
* par_beginschedule/endschedule: 
  - added support for scheduler changes, new encoding format and
par_globalsetting
  - increase spin interval from 100ms to 250ms
* Fixed an issue in bci_batchtrain: accidentally used a
non-fault-tolerant error handler when running locally
* env_startup: added support for verbosity setting
Merge remote-tracking branch 'origin/scheduling_update' into devel
Updated liblsl version.
Minor fix in run_writelsl and run_writesnap.