.Net client should send HELO command during bootstrap

Like other SDKs, the .Net sdk should send a HELO command during bootstrap. It should include the the SDK name and version number. It would also be useful to include the pool settings.

Currently a HELO command is only sent if useEnhancedDurability is explicitly set to true in the BucketConfiguration. This HELO command does not include the SDK name or version.

2016-08-03T10:30:00.302658Z NOTICE 42: HELO Mutation seqno [ 10.142.150.1:65486 - 10.142.150.101:11210 ]

2016-08-03T10:33:42.815814Z NOTICE 42: HELO Mutation seqno [ 10.142.150.1:65524 - 10.142.150.101:11210 ]

This functionality will make the behaviour more similar to that of the other SDKs which send a HELO command during bootstrap by default and send their SDK name and version. For example the Java SDK sends the following HELO command:

[couchbase-java-client/2.3.1 (git: 2.3.1, core: 1.3.1) (Mac OS X/10.11.6 x86_64; Java HotSpot(TM) 64-Bit Server VM 1.8.0_91-b14)] TCP NODELAY [ 10.142.150.1:57824 - 10.142.150.101:11210 ]

Additionally it is useful for support, if we can see from the logs which SDKs are connecting to the server and their version etc.