Command-line option to install as Local System

Added the ability to install the service using the Local System account
from the command-line.
This also requires an update to the docs at:
http://topshelf.readthedocs.org/en/latest/overview/commandline.html to
include the new parameter.
Setting ServiceBase.ServiceName so fatal errors make it to the Event Log
Updated docs for new command-line parameter

Added the new parameter for installing as Local System account to the
docs.
Fixed numbering not corresponding to the lines
Fixed log message for processing custom command.
Changed to use InfoFormat
Added StartTimeOut and StopTimeOut properties to HostSettings

to configure timeout values of StartService and StopService methods of HostEnvironment.
Update index.rst
Update NLog to 3.1.0 and resolve "obsolete" warnings
Flush buffers on unhandled exception to log message in case of async logger (close #171)
Merge pull request #196 from solyutor/flushbuffers

Flush log buffers on unhandled exception
Flush log buffers if HostFactory.New or HostFactory.Run throw exception
Merge pull request #201 from solyutor/flushbuffers2

Flush log buffers if HostFactory.New()/Run() throws an exception.
Updated build and version
Return error code for unhandled exceptions when running service under ConsoleHost

This makes the behaviour consistent with the WindowsServiceHost
Adding Elmah logging project as an alternative logging option
Conditionally reference Elmah for the .NET builds

An attempt to follow the patterns established how Log4Net and NLog are
set up.
Updated build for elmah logging
Mono runtime check on IsServiceInstalled method, returns false if Mono
detected.
Updated command-line to handle special characters