Implemented Data Collection Consent with PreferenceSetting(PersistentSetting)

Data Collection Consent
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Data Collection Consent Dialog will appear in the first run of Dynamo. 

User is allowed to change his/her choice though the setting menu option.
![image](https://f.cloud.github.com/assets/5276243/1511961/6b062c70-4abd-11e3-8ee3-7ed2aed6f7c8.png)

In the event of toggling the choice, when the choice is toggled to True. Consent Dialog will appeared for the user again. Only if the checkbox is checked and user click on continue, then it is set to true.

The actual information is actually store in PreferenceSettings which then be saved into xml located at:
"C:\Users\USERNAME\AppData\Roaming\Autodesk\Dynamo\DynamoSettings.xml".

For QA:
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To start afresh for first run, delete the xml file.
For shortcut to that folder run %APPDATA%\Autodesk\Dynamo

PreferenceSettings
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Settings that are persistent includes:
1) Show Console
2) Connector Type
3) Showing Background 3D view or Canvas view