Give the user help on checksum errors
add uninstall stanza for smoothmouse

per #2204.  Note: in testing, this uninstall is
imperfect, but should be complete after the next reboot.
Bump Xamarin Studio to v4.2.3
Add Xamarin.iOS at v7.2.1.25
Add Xamarin.Android at v4.12.3-3
Bump Mono MDK to v3.4.0.185
Fixing checksum for CrashPlan v3.6.3
Upgrade Genymotion.app to v2.2.0
Update Google App Engine Launcher to 1.9.1
Merge pull request #3758 from denysbutenko/master

Update Google App Engine Launcher to 1.9.1
Merge pull request #3757 from tolbkni/genymotion

Upgrade Genymotion.app to v2.2.0
Merge pull request #3755 from tolbkni/qq

Upgrade QQ.app to v3.1.1
Merge pull request #3756 from macprince/crashplan

Fixing checksum for CrashPlan v3.6.3
Add Ngrok v1.6

Initial commit for Ngrok
Merge pull request #3749 from rolandwalker/smoothmouse_uninstall

add uninstall stanza for smoothmouse
Merge pull request #3745 from jamesottaway/master

Xamarin Studio, incl. Xamarin.Android, Xamarin.iOS and Mono MDK
Upgrade OpenTTD to 1.4.0
Merge pull request #3761 from trevorparker/openttd-1-4-0

Upgrade OpenTTD to 1.4.0
Bumps Vagrant version to 1.5.2
Merge pull request #3762 from scottsuch/vagrant-1.5.2

Bumps Vagrant version to 1.5.2