fix FSharp sample build on vs2012
more explicit message if performance counters can't be read
report last value for histograms
update flot app to latest
implementation for a "null" registry where everything is a no-op
remove usage of Metrics & HealthChecks static classes as much as possible. Pass registries as parameters instead.
move registry interfaces to Core namespace as they are not normally used directly
refactor metrics config as separate class
remove test as its machine dependent
fix comments
FSharp build on osx
Merge branch 'master' of github.com:etishor/Metrics.NET
add two more units for size histograms
remove empty lines
overwrite the report file
move reports config to reports folder
refactor Nancy config to be consistent with MetricsConfig
make reports config chainable
chain nancy config in sample
move http listener config to MetricsConfig