Remove support for IIS classic mode

[kevinobee]

Remove any manipulation of the /configuration/system.web/httpModules/ section when installing Sitecore.Glimpse.

Currently if you install Sitecore.Glimpse.Mvc5 0.6.3 the package installation will fail with an as shown below:

PM> install-package  sitecore.glimpse.mvc5
Attempting to resolve dependency 'Glimpse.Mvc5 (≥ 1.5.3)'.
Attempting to resolve dependency 'Glimpse.AspNet (≥ 1.8.0)'.
Attempting to resolve dependency 'Glimpse (≥ 1.8.6)'.
Attempting to resolve dependency 'Glimpse.WebForms (≥ 1.1.1)'.
Installing 'Sitecore.Glimpse.Mvc5 0.6.3'.
Successfully installed 'Sitecore.Glimpse.Mvc5 0.6.3'.
Adding 'Sitecore.Glimpse.Mvc5 0.6.3' to Website.
'web.config' already exists. Skipping...
Uninstalling 'Sitecore.Glimpse.Mvc5 0.6.3'.
Successfully uninstalled 'Sitecore.Glimpse.Mvc5 0.6.3'.
Install failed. Rolling back...
install-package : An error occurred while applying transformation to 'web.config' in project 'Website': No element in the source document matches
'/configuration/system.web/httpModules/add'
    At line:1 char:1
    + install-package  sitecore.glimpse.mvc5
    + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        + CategoryInfo          : NotSpecified: (:) [Install-Package],     InvalidDataException
        + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand

[kevinobee]

Merged into develo in preparation for a release/0.7.0 branch being created.