Implemented a MemoryMonitor to debug memory consumption issues
first implementation
more work... updated bcr. unit tests of getters
Merge branch 'scenario-insured' into event-loss-tables
Merge branch 'master' of github.com:gem/oq-engine into performance-monitor
Enhanced the PerformanceMonitor and relative tests
Added forgotten file
added qa test for event loss table
Merge branch 'master' of https://github.com/gem/oq-engine into event-loss-tables
Merged from master
Added python-psutil dependency
Merge branch 'master' of https://github.com/gem/oq-engine into event-loss-tables
Merged from master
improved docs
performance:

Recover gracefully if psutil can't read process memory info due to an
AccessDenied error. If this happens, the process in question is discarded
from the monitored and is not checked anymore.
Various fixes according to Luigi suggestions
Small improvements to the PerformanceMonitor
Merge branch 'master' of https://github.com/gem/oq-engine into event-loss-tables
added clarifying comments
Removed a debug statement