Reduce Exceptions thrown during type conversions.

There are tons of places where null, blank or empty strings are being
converted to primative types (like int,, long, etc) or other ValueTypes
(like Guid, DateTime, etc.). When this is attempted, Exceptions are
thrown (and caught/swallowed) to allow for value defaulting. Since this
happens all the time in normal operation, tons of Exceptions are being
thrown. By switching to the TryParse methods available on all primative
types and the interesting ValueTypes, we can greatly speed the
processing of content data.
Merge pull request #172 from IDisposable/6.2.0

Reduce Exceptions thrown during type conversions.
Fixes: U4-3193 Partial view cache needs to invalidate based on cache refreshers
Merge remote-tracking branch 'origin/6.2.0' into 6.2.0-membershipprovider
Adds Xml output for members to packaging service and ToXml extensions, updates examine event handler to listen to new member events as well as old (until we fix that). Adds events to MemberService
Merge remote-tracking branch 'origin/6.2.0-membershipprovider' into 7.0.0

Conflicts:
	src/Umbraco.Tests/ObjectExtensionsTests.cs
	src/Umbraco.Web/WebBootManager.cs
Listens to new member events for cache refreshing