Switch SpikeMonitor implementation to code generation
Do the scipy mocking earlier in the Sphinx configuration
Fix wrong handling of division on state variables
Create pointers also for variables mentioned in USE_SPECIFIERS
Make sure to use the correct datatype for synapse creation
Allow recording of subexpressions that lead to a scalar value
Make sure to deal correctly with the not_refractory variable (see #38)
Deal with stochastic equations that multiply xi with 0 (might occur during testing)
Make sure all examples work
Start implementing StateMonitor with code generation (not working yet)
Python codegeneration working for StateMonitor
C++ codegeneration working for StateMonitor
Merge remote-tracking branch 'origin/master' into monitors_codegen

Conflicts:
	brian2/codegen/languages/base.py
	brian2/codegen/runtime/numpy_rt/templates/monitor.py_
	brian2/codegen/runtime/weave_rt/templates/monitor.cpp
	brian2/monitors/statemonitor.py
Fix recording several state variables with C++ code
Use numpy_resize for DynamicArrays
Make StateMonitor work again for subexpressions
Switch off refchecks for synaptic indices -- this way we can use the faster resize. No code should ever store a reference to the underlying data attribute.
Use numpy's concatenate instead of hstack, it's apparently faster
Fix bugs and add tests for StateMonitor, no longer derive from Groups (this doesn't play nicely with subexpressions)
Fix an incorrect import that sneaked in