Fixed dual stack router template.
Modifed chunk demo code to rerequest dropped CIDs.
Merge branch 'develop'
Update README.md
Provid SID at bind. Accept autogenerates SID.

These SIDs must have corresponding keys in the "key" directory.
Autodetect key directory path relative to XrootDir
Echoserver now creates a key pair and uses its SID
User facing API just deals with SID strings now

Also supporting deleting a requested key pair based on SID.
Switching printfs with LOG/LOGF macros.
Remove String sdag & ddag from DAGinfo

They were redundant because the source and destination DAGs are already
stored as XIApath variables in the DAGinfo. Leaving the String versions
can lead to inconsistencies where one type is updated but not the other.
Migrate and MigrateACK transport headers
Added function to get the xia root directory.
Added function to get xia root directory.
Merge branch 'develop' into intrinsic_security
Intrinsic security abstraction

The new xiasecurity module provides generic functions to perform
intrinsic security operations.
Remove seq_num from daginfo in xtransport

It was identical to next_seqnum.
Fixed typo :: not :
Inform all active sessions to migrate

With this change, all active sessions send out a MIGRATE message to
their corresponding peers. The MIGRATE message includes the source DAG,
the destination DAG, current Timestamp, all signed with the source SID
private key. The public key for source SID is also included in the
MIGRATE messages so it can be used for verification at the receiver.

The code for processing received MIGRATE and MIGRATEACK messages is
currently incomplete.

This change also updates the xiasecurity API to better serve the needs
of Xtransport::Xchangead().
MIGRATE intrinsic security checks

We retrieve the MIGRATE payload from the packet and verify:
* Source address matches the public key
* Signature is valid

We currently ignore the timestamp. Should compare against last migration
time to ensure this packet is not being replayed.
Signed MIGRATEACK sent in response to MIGRATE